feat: SlickVPN Support (#961)

- `internal/updater/html` package
- Add unit tests for slickvpn updating code
- Change shared html package to be more share-able
- Split html utilities in multiple files
- Fix processing .ovpn files with prefix space

Authored by @Rohaq 
Co-authored-by: Quentin McGaw <quentin.mcgaw@gmail.com>

.github/ISSUE_TEMPLATE/bug.yml

@@ -54,6 +54,7 @@ body:
         - PrivateVPN
         - ProtonVPN
         - PureVPN
+        - SlickVPN
         - Surfshark
         - TorGuard
         - VPNUnlimited

.github/labels.yml

@@ -64,6 +64,9 @@
 - name: ":cloud: PureVPN"
   color: "cfe8d4"
   description: ""
+- name: ":cloud: SlickVPN"
+  color: "cfe8d4"
+  description: ""
 - name: ":cloud: Surfshark"
   color: "cfe8d4"
   description: ""

go.mod

@@ -17,6 +17,7 @@ require (
 	github.com/qdm12/updated v0.0.0-20210603204757-205acfe6937e
 	github.com/stretchr/testify v1.8.0
 	github.com/vishvananda/netlink v1.1.1-0.20211129163951-9ada19101fc5
+	golang.org/x/net v0.0.0-20210916014120-12bc252f5db8
 	golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c
 	golang.org/x/text v0.3.7
 	golang.zx2c4.com/wireguard v0.0.0-20210805125648-3957e9b9dd19
@@ -40,6 +41,5 @@ require (
 	go4.org/intern v0.0.0-20210108033219-3eb7198706b2 // indirect
 	go4.org/unsafe/assume-no-moving-gc v0.0.0-20220617031537-928513b29760 // indirect
 	golang.org/x/crypto v0.0.0-20210711020723-a769d52b0f97 // indirect
-	golang.org/x/net v0.0.0-20210504132125-bbd867fde50d // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -179,8 +179,9 @@ golang.org/x/net v0.0.0-20201224014010-6772e930b67b/go.mod h1:m0MpNAwzfU5UDzcl9v
 golang.org/x/net v0.0.0-20210119194325-5f4716e94777/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
-golang.org/x/net v0.0.0-20210504132125-bbd867fde50d h1:nTDGCTeAu2LhcsHTRzjyIUbZHCJ4QePArsm27Hka0UM=
 golang.org/x/net v0.0.0-20210504132125-bbd867fde50d/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/net v0.0.0-20210916014120-12bc252f5db8 h1:/6y1LfuqNuQdHAm0jjtPtgRcxIxjVZgm5OTu8/QhZvk=
+golang.org/x/net v0.0.0-20210916014120-12bc252f5db8/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20210220032951-036812b2e83c h1:5KslGYwFpkhGh+Q16bwMP3cOontH8FOep7tGV86Y7SQ=

internal/configuration/settings/openvpnselection.go

@@ -82,6 +82,9 @@ func (o OpenVPNSelection) validate(vpnProvider string) (err error) {
 			case providers.Protonvpn:
 				allowedTCP = []uint16{443, 5995, 8443}
 				allowedUDP = []uint16{80, 443, 1194, 4569, 5060}
+			case providers.SlickVPN:
+				allowedTCP = []uint16{443, 8080, 8888}
+				allowedUDP = []uint16{443, 8080, 8888}
 			case providers.Wevpn:
 				allowedTCP = []uint16{53, 1195, 1199, 2018}
 				allowedUDP = []uint16{80, 1194, 1198}

internal/constants/providers/providers.go

@@ -19,6 +19,7 @@ const (
 	Privatevpn            = "privatevpn"
 	Protonvpn             = "protonvpn"
 	Purevpn               = "purevpn"
+	SlickVPN              = "slickvpn"
 	Surfshark             = "surfshark"
 	Torguard              = "torguard"
 	VPNUnlimited          = "vpn unlimited"
@@ -44,6 +45,7 @@ func All() []string {
 		Privatevpn,
 		Protonvpn,
 		Purevpn,
+		SlickVPN,
 		Surfshark,
 		Torguard,
 		VPNUnlimited,

internal/models/markdown.go

@@ -123,6 +123,8 @@ func getMarkdownHeaders(vpnProvider string) (headers []string) {
 		return []string{countryHeader, regionHeader, cityHeader, hostnameHeader, freeHeader}
 	case providers.Purevpn:
 		return []string{countryHeader, regionHeader, cityHeader, hostnameHeader, tcpHeader, udpHeader}
+	case providers.SlickVPN:
+		return []string{regionHeader, countryHeader, cityHeader, hostnameHeader}
 	case providers.Surfshark:
 		return []string{regionHeader, countryHeader, cityHeader, hostnameHeader, multiHopHeader, tcpHeader, udpHeader}
 	case providers.Torguard:

internal/provider/hidemyass/updater/hosttourl.go

@@ -33,5 +33,11 @@ func getHostToURL(ctx context.Context, client *http.Client, protocol string) (
 		return nil, err
 	}
 
-	return openvpn.FetchMultiFiles(ctx, client, urls)
+	const failEarly = true
+	hostToURL, errors := openvpn.FetchMultiFiles(ctx, client, urls, failEarly)
+	if len(errors) > 0 {
+		return nil, errors[0]
+	}
+
+	return hostToURL, nil
 }

internal/provider/providers.go

@@ -25,6 +25,7 @@ import (
 	"github.com/qdm12/gluetun/internal/provider/privatevpn"
 	"github.com/qdm12/gluetun/internal/provider/protonvpn"
 	"github.com/qdm12/gluetun/internal/provider/purevpn"
+	"github.com/qdm12/gluetun/internal/provider/slickvpn"
 	"github.com/qdm12/gluetun/internal/provider/surfshark"
 	"github.com/qdm12/gluetun/internal/provider/torguard"
 	"github.com/qdm12/gluetun/internal/provider/vpnunlimited"
@@ -71,6 +72,7 @@ func NewProviders(storage Storage, timeNow func() time.Time,
 		providers.Privatevpn:            privatevpn.New(storage, randSource, unzipper, updaterWarner, parallelResolver),
 		providers.Protonvpn:             protonvpn.New(storage, randSource, client, updaterWarner, parallelResolver),
 		providers.Purevpn:               purevpn.New(storage, randSource, ipFetcher, unzipper, updaterWarner, parallelResolver),
+		providers.SlickVPN:              slickvpn.New(storage, randSource, client, updaterWarner, parallelResolver),
 		providers.Surfshark:             surfshark.New(storage, randSource, client, unzipper, updaterWarner, parallelResolver),
 		providers.Torguard:              torguard.New(storage, randSource, unzipper, updaterWarner, parallelResolver),
 		providers.VPNUnlimited:          vpnunlimited.New(storage, randSource, unzipper, updaterWarner, parallelResolver),

internal/provider/slickvpn/connection.go

@@ -0,0 +1,13 @@
+package slickvpn
+
+import (
+	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/provider/utils"
+)
+
+func (p *Provider) GetConnection(selection settings.ServerSelection) (
+	connection models.Connection, err error) {
+	defaults := utils.NewConnectionDefaults(0, 443, 0) //nolint:gomnd
+	return utils.GetConnection(p.Name(), p.storage, selection, defaults, p.randSource)
+}

internal/provider/slickvpn/openvpnconf.go

@@ -0,0 +1,30 @@
+package slickvpn
+
+import (
+	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/gluetun/internal/constants/openvpn"
+	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/provider/utils"
+)
+
+func (p *Provider) OpenVPNConfig(connection models.Connection,
+	settings settings.OpenVPN) (lines []string) {
+	const pingSeconds = 10
+	const bufSize = 393216
+	providerSettings := utils.OpenVPNProviderSettings{
+		RemoteCertTLS: true,
+		AuthUserPass:  true,
+		Ciphers: []string{
+			openvpn.AES256cbc,
+		},
+		Ping:   pingSeconds,
+		SndBuf: bufSize,
+		RcvBuf: bufSize,
+		// Certificate found from https://www.slickvpn.com/tutorials/using-openvpn-configuration-files/
+		CA: "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", //nolint:lll
+		ExtraLines: []string{
+			"redirect-gateway",
+		},
+	}
+	return utils.OpenVPNConfig(providerSettings, connection, settings)
+}

internal/provider/slickvpn/provider.go

@@ -0,0 +1,33 @@
+package slickvpn
+
+import (
+	"math/rand"
+	"net/http"
+
+	"github.com/qdm12/gluetun/internal/constants/providers"
+	"github.com/qdm12/gluetun/internal/provider/common"
+	"github.com/qdm12/gluetun/internal/provider/slickvpn/updater"
+	"github.com/qdm12/gluetun/internal/provider/utils"
+)
+
+type Provider struct {
+	storage    common.Storage
+	randSource rand.Source
+	utils.NoPortForwarder
+	common.Fetcher
+}
+
+func New(storage common.Storage, randSource rand.Source,
+	client *http.Client, updaterWarner common.Warner,
+	parallelResolver common.ParallelResolver) *Provider {
+	return &Provider{
+		storage:         storage,
+		randSource:      randSource,
+		NoPortForwarder: utils.NewNoPortForwarding(providers.SlickVPN),
+		Fetcher:         updater.New(client, updaterWarner, parallelResolver),
+	}
+}
+
+func (p *Provider) Name() string {
+	return providers.SlickVPN
+}

internal/provider/slickvpn/updater/helpers_test.go

@@ -0,0 +1,26 @@
+package updater
+
+import (
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"golang.org/x/net/html"
+)
+
+func parseTestHTML(t *testing.T, htmlString string) *html.Node {
+	t.Helper()
+	rootNode, err := html.Parse(strings.NewReader(htmlString))
+	require.NoError(t, err)
+	return rootNode
+}
+
+func parseTestDataIndexHTML(t *testing.T) *html.Node {
+	t.Helper()
+
+	data, err := os.ReadFile("testdata/index.html")
+	require.NoError(t, err)
+
+	return parseTestHTML(t, string(data))
+}

internal/provider/slickvpn/updater/resolve.go

@@ -0,0 +1,28 @@
+package updater
+
+import (
+	"time"
+
+	"github.com/qdm12/gluetun/internal/updater/resolver"
+)
+
+func parallelResolverSettings(hosts []string) (settings resolver.ParallelSettings) {
+	const (
+		maxFailRatio    = 0.1
+		maxDuration     = 20 * time.Second
+		betweenDuration = time.Second
+		maxNoNew        = 2
+		maxFails        = 2
+	)
+	return resolver.ParallelSettings{
+		Hosts:        hosts,
+		MaxFailRatio: maxFailRatio,
+		Repeat: resolver.RepeatSettings{
+			MaxDuration:     maxDuration,
+			BetweenDuration: betweenDuration,
+			MaxNoNew:        maxNoNew,
+			MaxFails:        maxFails,
+			SortIPs:         true,
+		},
+	}
+}

internal/provider/slickvpn/updater/servers.go

@@ -0,0 +1,82 @@
+package updater
+
+import (
+	"context"
+	"fmt"
+	"sort"
+
+	"github.com/qdm12/gluetun/internal/constants/vpn"
+	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/provider/common"
+	"github.com/qdm12/gluetun/internal/updater/openvpn"
+)
+
+func (u *Updater) FetchServers(ctx context.Context, minServers int) (
+	servers []models.Server, err error) {
+	hostToData, err := fetchServers(ctx, u.client)
+	if err != nil {
+		return nil, fmt.Errorf("fetching and parsing website: %w", err)
+	}
+
+	openvpnURLs := make([]string, 0, len(hostToData))
+	for _, data := range hostToData {
+		openvpnURLs = append(openvpnURLs, data.ovpnURL)
+	}
+
+	if len(openvpnURLs) < minServers {
+		return nil, fmt.Errorf("%w: %d and expected at least %d",
+			common.ErrNotEnoughServers, len(openvpnURLs), minServers)
+	}
+
+	const failEarly = false // some URLs from the website are not valid
+	udpHostToURL, errors := openvpn.FetchMultiFiles(ctx, u.client, openvpnURLs, failEarly)
+	for _, err := range errors {
+		u.warner.Warn(fmt.Sprintf("fetching OpenVPN files: %s", err))
+	}
+
+	if len(udpHostToURL) < minServers {
+		return nil, fmt.Errorf("%w: %d and expected at least %d",
+			common.ErrNotEnoughServers, len(udpHostToURL), minServers)
+	}
+
+	hosts := make([]string, 0, len(udpHostToURL))
+	for host := range udpHostToURL {
+		hosts = append(hosts, host)
+	}
+
+	resolveSettings := parallelResolverSettings(hosts)
+	hostToIPs, warnings, err := u.parallelResolver.Resolve(ctx, resolveSettings)
+	for _, warning := range warnings {
+		u.warner.Warn(warning)
+	}
+	if err != nil {
+		return nil, fmt.Errorf("resolving hosts: %w", err)
+	}
+
+	if len(hostToIPs) < minServers {
+		return nil, fmt.Errorf("%w: %d and expected at least %d",
+			common.ErrNotEnoughServers, len(hosts), minServers)
+	}
+
+	servers = make([]models.Server, 0, len(hostToIPs))
+	for host, IPs := range hostToIPs {
+		_, udp := udpHostToURL[host]
+
+		serverData := hostToData[host]
+
+		server := models.Server{
+			VPN:      vpn.OpenVPN,
+			Region:   serverData.region,
+			Country:  serverData.country,
+			City:     serverData.city,
+			Hostname: host,
+			UDP:      udp,
+			IPs:      IPs,
+		}
+		servers = append(servers, server)
+	}
+
+	sort.Sort(models.SortableServers(servers))
+
+	return servers, nil
+}

internal/provider/slickvpn/updater/updater.go

@@ -0,0 +1,22 @@
+package updater
+
+import (
+	"net/http"
+
+	"github.com/qdm12/gluetun/internal/provider/common"
+)
+
+type Updater struct {
+	client           *http.Client
+	parallelResolver common.ParallelResolver
+	warner           common.Warner
+}
+
+func New(client *http.Client, warner common.Warner,
+	parallelResolver common.ParallelResolver) *Updater {
+	return &Updater{
+		client:           client,
+		parallelResolver: parallelResolver,
+		warner:           warner,
+	}
+}

internal/provider/slickvpn/updater/website.go

@@ -0,0 +1,181 @@
+package updater
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"regexp"
+
+	htmlutils "github.com/qdm12/gluetun/internal/updater/html"
+	"golang.org/x/net/html"
+)
+
+func fetchServers(ctx context.Context, client *http.Client) (
+	hostToData map[string]serverData, err error) {
+	rootNode, err := fetchHTML(ctx, client)
+	if err != nil {
+		return nil, fmt.Errorf("fetching HTML code: %w", err)
+	}
+
+	hostToData, err = parseHTML(rootNode)
+	if err != nil {
+		return nil, fmt.Errorf("parsing HTML: %w", err)
+	}
+
+	return hostToData, nil
+}
+
+var ErrHTTPStatusCode = errors.New("HTTP status code is not OK")
+
+func fetchHTML(ctx context.Context, client *http.Client) (rootNode *html.Node, err error) {
+	const url = "https://www.slickvpn.com/locations/"
+	request, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	response, err := client.Do(request)
+	if err != nil {
+		return nil, err
+	}
+
+	if response.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("%w: %d %s",
+			ErrHTTPStatusCode, response.StatusCode, response.Status)
+	}
+
+	rootNode, err = html.Parse(response.Body)
+	if err != nil {
+		_ = response.Body.Close()
+		return nil, fmt.Errorf("parsing HTML code: %w", err)
+	}
+
+	err = response.Body.Close()
+	if err != nil {
+		return nil, fmt.Errorf("closing response body: %w", err)
+	}
+
+	return rootNode, nil
+}
+
+type serverData struct {
+	ovpnURL string
+	country string
+	region  string
+	city    string
+}
+
+var (
+	ErrLocationTableNotFound = errors.New("HTML location table node not found")
+	ErrTbodyNotFound         = errors.New("HTML tbody node not found")
+	ErrExtractOpenVPNURL     = errors.New("failed extracting OpenVPN URL")
+)
+
+func parseHTML(rootNode *html.Node) (hostToData map[string]serverData, err error) {
+	locationTableNode := htmlutils.BFS(rootNode, matchLocationTable)
+	if locationTableNode == nil {
+		return nil, htmlutils.WrapError(ErrLocationTableNotFound, rootNode)
+	}
+
+	tBodyNode := htmlutils.BFS(locationTableNode, matchTbody)
+	if tBodyNode == nil {
+		return nil, htmlutils.WrapError(ErrTbodyNotFound, rootNode)
+	}
+
+	rowNodes := htmlutils.DirectChildren(tBodyNode, matchTr)
+	hostToData = make(map[string]serverData, len(rowNodes))
+
+	for _, rowNode := range rowNodes {
+		hostname, data, err := parseRowNode(rowNode)
+		if err != nil {
+			return nil, fmt.Errorf("parsing row node: %w", err)
+		}
+		hostToData[hostname] = data
+	}
+
+	return hostToData, nil
+}
+
+func parseRowNode(rowNode *html.Node) (hostname string, data serverData, err error) {
+	columnIndex := 0
+	const (
+		columnIndexContinent = 0
+		columnIndexCountry   = 1
+		columnIndexCity      = 2
+		columnIndexConfig    = 3
+	)
+	for cellNode := rowNode.FirstChild; cellNode != nil; cellNode = cellNode.NextSibling {
+		if cellNode.FirstChild == nil {
+			continue
+		}
+
+		switch columnIndex {
+		case columnIndexContinent:
+			data.region = cellNode.FirstChild.Data
+		case columnIndexCountry:
+			data.country = cellNode.FirstChild.Data
+		case columnIndexCity:
+			data.city = cellNode.FirstChild.Data
+		case columnIndexConfig:
+			linkNodes := htmlutils.DirectChildren(cellNode, matchA)
+			for _, linkNode := range linkNodes {
+				if linkNode.FirstChild.Data != "OpenVPN" {
+					continue
+				}
+
+				data.ovpnURL = htmlutils.Attribute(linkNode, "href")
+				if data.ovpnURL == "" {
+					return "", data, htmlutils.WrapError(ErrExtractOpenVPNURL, linkNode)
+				}
+
+				hostname, err = extractHostnameFromURL(data.ovpnURL)
+				if err != nil {
+					return "", data, fmt.Errorf("extracting hostname from url: %w", err)
+				}
+
+				break
+			}
+		}
+
+		columnIndex++
+		if columnIndex == columnIndexConfig+1 {
+			break
+		}
+	}
+
+	return hostname, data, nil
+}
+
+func matchLocationTable(rootNode *html.Node) (match bool) {
+	return htmlutils.MatchID("location-table")(rootNode)
+}
+
+func matchTbody(locationTableNode *html.Node) (match bool) {
+	return htmlutils.MatchData("tbody")(locationTableNode)
+}
+
+func matchTr(tbodyNode *html.Node) (match bool) {
+	return htmlutils.MatchData("tr")(tbodyNode)
+}
+
+func matchA(cellNode *html.Node) (match bool) {
+	return htmlutils.MatchData("a")(cellNode)
+}
+
+var serverNameRegex = regexp.MustCompile(`^.+\/(?P<serverName>.+)\.ovpn$`)
+
+var (
+	ErrExtractHostnameFromURL = errors.New("cannot extract hostname from url")
+)
+
+func extractHostnameFromURL(url string) (hostname string, err error) {
+	matches := serverNameRegex.FindStringSubmatch(url)
+	const minMatches = 2
+	if len(matches) < minMatches {
+		return "", fmt.Errorf("%w: %s has less than 2 matches for %s",
+			ErrExtractHostnameFromURL, url, serverNameRegex)
+	}
+	hostname = matches[1]
+	return hostname, nil
+}

internal/provider/slickvpn/updater/website_test.go

@@ -0,0 +1,337 @@
+package updater
+
+import (
+	"context"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"golang.org/x/net/html"
+)
+
+type roundTripFunc func(r *http.Request) (*http.Response, error)
+
+func (f roundTripFunc) RoundTrip(r *http.Request) (*http.Response, error) {
+	return f(r)
+}
+
+func Test_fetchServers(t *testing.T) {
+	t.Parallel()
+
+	canceledCtx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	testCases := map[string]struct {
+		ctx            context.Context
+		responseStatus int
+		responseBody   io.ReadCloser
+		hostToData     map[string]serverData
+		errWrapped     error
+		errMessage     string
+	}{
+		"context canceled": {
+			ctx:        canceledCtx,
+			errWrapped: context.Canceled,
+			errMessage: `fetching HTML code: Get "https://www.slickvpn.com/locations/": context canceled`,
+		},
+		"success": {
+			ctx:            context.Background(),
+			responseStatus: http.StatusOK,
+			//nolint:lll
+			responseBody: ioutil.NopCloser(strings.NewReader(`
+			<div>
+				<table id="location-table">
+					<tbody>
+						<tr>
+							<td>South America</td>
+							<td>Chile</td>
+							<td>Vina del Mar</td>
+							<td> <a
+									href="https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.kna1.slickvpn.com.ovpn">OpenVPN</a>
+								| <a
+									href="https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/viscosity/gw1.kna1.slickvpn.com_viscosity.ovpn">Viscosity</a>
+							</td>
+						</tr>
+					</tbody>
+				</table>
+			</div>
+			`)),
+			hostToData: map[string]serverData{
+				"gw1.kna1.slickvpn.com": {
+					ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.kna1.slickvpn.com.ovpn", //nolint:lll
+					country: "Chile",
+					region:  "South America",
+					city:    "Vina del Mar",
+				},
+			},
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			client := &http.Client{
+				Transport: roundTripFunc(func(r *http.Request) (*http.Response, error) {
+					assert.Equal(t, http.MethodGet, r.Method)
+					assert.Equal(t, r.URL.String(), "https://www.slickvpn.com/locations/")
+
+					ctxErr := r.Context().Err()
+					if ctxErr != nil {
+						return nil, ctxErr
+					}
+
+					return &http.Response{
+						StatusCode: http.StatusOK,
+						Status:     http.StatusText(testCase.responseStatus),
+						Body:       testCase.responseBody,
+					}, nil
+				}),
+			}
+
+			hostToData, err := fetchServers(testCase.ctx, client)
+
+			assert.ErrorIs(t, err, testCase.errWrapped)
+			if testCase.errWrapped != nil {
+				assert.EqualError(t, err, testCase.errMessage)
+			}
+			assert.Equal(t, testCase.hostToData, hostToData)
+		})
+	}
+}
+
+func Test_fetchHTML(t *testing.T) {
+	t.Parallel()
+
+	canceledCtx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	testCases := map[string]struct {
+		ctx            context.Context
+		responseStatus int
+		responseBody   io.ReadCloser
+		rootNode       *html.Node
+		errWrapped     error
+		errMessage     string
+	}{
+		"context canceled": {
+			ctx:        canceledCtx,
+			errWrapped: context.Canceled,
+			errMessage: `Get "https://www.slickvpn.com/locations/": context canceled`,
+		},
+		"response status not ok": {
+			ctx:            context.Background(),
+			responseStatus: http.StatusNotFound,
+			errWrapped:     ErrHTTPStatusCode,
+			errMessage:     `HTTP status code is not OK: 404 Not Found`,
+		},
+		"success": {
+			ctx:            context.Background(),
+			responseStatus: http.StatusOK,
+			rootNode:       parseTestHTML(t, "some body"),
+			responseBody:   ioutil.NopCloser(strings.NewReader("some body")),
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			client := &http.Client{
+				Transport: roundTripFunc(func(r *http.Request) (*http.Response, error) {
+					assert.Equal(t, http.MethodGet, r.Method)
+					assert.Equal(t, r.URL.String(), "https://www.slickvpn.com/locations/")
+
+					ctxErr := r.Context().Err()
+					if ctxErr != nil {
+						return nil, ctxErr
+					}
+
+					return &http.Response{
+						StatusCode: testCase.responseStatus,
+						Status:     http.StatusText(testCase.responseStatus),
+						Body:       testCase.responseBody,
+					}, nil
+				}),
+			}
+
+			rootNode, err := fetchHTML(testCase.ctx, client)
+
+			assert.ErrorIs(t, err, testCase.errWrapped)
+			if testCase.errWrapped != nil {
+				assert.EqualError(t, err, testCase.errMessage)
+			}
+			assert.Equal(t, testCase.rootNode, rootNode)
+		})
+	}
+}
+
+func Test_parseHTML(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		rootNode   *html.Node
+		hostToData map[string]serverData
+		errWrapped error
+		errMessage string
+	}{
+		"empty html": {
+			rootNode:   parseTestHTML(t, ""),
+			errWrapped: ErrLocationTableNotFound,
+			errMessage: `HTML location table node not found: in HTML code: <html><head></head><body></body></html>`,
+		},
+		"test data": {
+			rootNode: parseTestDataIndexHTML(t),
+			//nolint:lll
+			hostToData: map[string]serverData{
+				"gw1.ams1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.ams1.slickvpn.com.ovpn", country: "Netherlands", region: "Europe", city: "Amsterdam"},
+				"gw1.ams2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.ams2.slickvpn.com.ovpn", country: "Netherlands", region: "Europe", city: "Amsterdam"},
+				"gw1.ams3.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.ams3.slickvpn.com.ovpn", country: "Netherlands", region: "Europe", city: "Amsterdam"},
+				"gw1.ams4.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.ams4.slickvpn.com.ovpn", country: "Netherlands", region: "Europe", city: "Amsterdam"},
+				"gw1.arn1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.arn1.slickvpn.com.ovpn", country: "Sweden", region: "Europe", city: "Stockholm"},
+				"gw1.arn3.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.arn3.slickvpn.com.ovpn", country: "Sweden", region: "Europe", city: "Stockholm"},
+				"gw1.ath1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.ath1.slickvpn.com.ovpn", country: "Greece", region: "Europe", city: "Athens"},
+				"gw1.atl1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.atl1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Atlanta"},
+				"gw1.atl3.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.atl3.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Atlanta"},
+				"gw1.beg1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.beg1.slickvpn.com.ovpn", country: "Serbia", region: "Europe", city: "Belgrade"},
+				"gw1.bkk1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.bkk1.slickvpn.com.ovpn", country: "Thailand", region: "Asia", city: "Bangkok"},
+				"gw1.blr1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.blr1.slickvpn.com.ovpn", country: "India", region: "Asia", city: "Bangalore"},
+				"gw1.bne1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.bne1.slickvpn.com.ovpn", country: "Australia", region: "Oceania", city: "Brisbane"},
+				"gw1.bom1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.bom1.slickvpn.com.ovpn", country: "India", region: "Asia", city: "Mumbai"},
+				"gw1.bos1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.bos1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Boston"},
+				"gw1.bud1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.bud1.slickvpn.com.ovpn", country: "Hungary", region: "Europe", city: "Budapest"},
+				"gw1.buf1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.buf1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Buffalo"},
+				"gw1.buh2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.buh2.slickvpn.com.ovpn", country: "Romania", region: "Europe", city: "Bucharest"},
+				"gw1.cdg1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.cdg1.slickvpn.com.ovpn", country: "France", region: "Europe", city: "Paris"},
+				"gw1.cgk1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.cgk1.slickvpn.com.ovpn", country: "Indonesia", region: "Asia", city: "Jakarta"},
+				"gw1.cmh1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.cmh1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Columbus"},
+				"gw1.cph1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.cph1.slickvpn.com.ovpn", country: "Denmark", region: "Europe", city: "Copenhagen"},
+				"gw1.cvt1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.cvt1.slickvpn.com.ovpn", country: "United Kingdom", region: "Europe", city: "Coventry"},
+				"gw1.dbq1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.dbq1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Dubuque"},
+				"gw1.den1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.den1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Denver"},
+				"gw1.dfw2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.dfw2.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Dallas"},
+				"gw1.dfw3.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.dfw3.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Dallas"},
+				"gw1.dub1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.dub1.slickvpn.com.ovpn", country: "Ireland", region: "Europe", city: "Dublin"},
+				"gw1.ewr1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.ewr1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Newark"},
+				"gw1.fra1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.fra1.slickvpn.com.ovpn", country: "Germany", region: "Europe", city: "Frankfurt"},
+				"gw1.fra2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.fra2.slickvpn.com.ovpn", country: "Germany", region: "Europe", city: "Frankfurt"},
+				"gw1.gru2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.gru2.slickvpn.com.ovpn", country: "Brazil", region: "South America", city: "Sao Paulo"},
+				"gw1.grz1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.grz1.slickvpn.com.ovpn", country: "Austria", region: "Europe", city: "Graz"},
+				"gw1.had2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.had2.slickvpn.com.ovpn", country: "Sweden", region: "Europe", city: "Halmstad"},
+				"gw1.hkg2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.hkg2.slickvpn.com.ovpn", country: "Hong Kong", region: "Asia", city: "Hong Kong"},
+				"gw1.iad1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.iad1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Washington"},
+				"gw1.iev1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.iev1.slickvpn.com.ovpn", country: "Ukraine", region: "Europe", city: "Kiev"},
+				"gw1.iom1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.iom1.slickvpn.com.ovpn", country: "United Kingdom", region: "Europe", city: "Isle Of Man"},
+				"gw1.kiv1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.kiv1.slickvpn.com.ovpn", country: "Moldova", region: "Europe", city: "Chisinau"},
+				"gw1.kna1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.kna1.slickvpn.com.ovpn", country: "Chile", region: "South America", city: "Vina del Mar"},
+				"gw1.kul1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.kul1.slickvpn.com.ovpn", country: "Malaysia", region: "Asia", city: "Kuala Lumpur"},
+				"gw1.las1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.las1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Las Vegas"},
+				"gw1.lax1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.lax1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Los Angeles"},
+				"gw1.lax2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.lax2.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Los Angeles"},
+				"gw1.led1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.led1.slickvpn.com.ovpn", country: "Russian Federation", region: "Europe", city: "St Petersburg"},
+				"gw1.lga1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.lga1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "New York"},
+				"gw1.lga2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.lga2.slickvpn.com.ovpn", country: "United States", region: "North America", city: "New York"},
+				"gw1.lhr1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.lhr1.slickvpn.com.ovpn", country: "United Kingdom", region: "Europe", city: "London"},
+				"gw1.lhr2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.lhr2.slickvpn.com.ovpn", country: "United Kingdom", region: "Europe", city: "London"},
+				"gw1.lil1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.lil1.slickvpn.com.ovpn", country: "France", region: "Europe", city: "Lille"},
+				"gw1.lju1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.lju1.slickvpn.com.ovpn", country: "Slovenia", region: "Europe", city: "Ljubljana"},
+				"gw1.mad1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.mad1.slickvpn.com.ovpn", country: "Spain", region: "Europe", city: "Madrid"},
+				"gw1.man2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.man2.slickvpn.com.ovpn", country: "United Kingdom", region: "Europe", city: "Manchester"},
+				"gw1.mci2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.mci2.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Kansas City"},
+				"gw1.mrn1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.mrn1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Morganton"},
+				"gw1.mxp1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.mxp1.slickvpn.com.ovpn", country: "Italy", region: "Europe", city: "Milan"},
+				"gw1.mxp2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.mxp2.slickvpn.com.ovpn", country: "Italy", region: "Europe", city: "Milan"},
+				"gw1.nrt1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.nrt1.slickvpn.com.ovpn", country: "Japan", region: "Asia", city: "Tokyo"},
+				"gw1.nue1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.nue1.slickvpn.com.ovpn", country: "Germany", region: "Europe", city: "Nürnberg"},
+				"gw1.ord3.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.ord3.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Chicago"},
+				"gw1.ord4.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.ord4.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Chicago"},
+				"gw1.ost2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.ost2.slickvpn.com.ovpn", country: "Belgium", region: "Europe", city: "Ostend"},
+				"gw1.pao1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.pao1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Palo Alto"},
+				"gw1.phx2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.phx2.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Phoenix"},
+				"gw1.prg1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.prg1.slickvpn.com.ovpn", country: "Czech Republic", region: "Europe", city: "Prague"},
+				"gw1.prg2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.prg2.slickvpn.com.ovpn", country: "Czech Republic", region: "Europe", city: "Prague"},
+				"gw1.rcs1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.rcs1.slickvpn.com.ovpn", country: "United Kingdom", region: "Europe", city: "Rochester"},
+				"gw1.rkv1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.rkv1.slickvpn.com.ovpn", country: "Iceland", region: "Europe", city: "Reykjavik"},
+				"gw1.san1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.san1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "San Diego"},
+				"gw1.sea1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.sea1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Seattle"},
+				"gw1.sea2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.sea2.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Seattle"},
+				"gw1.sin1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.sin1.slickvpn.com.ovpn", country: "Singapore", region: "Asia", city: "Singapore"},
+				"gw1.sin2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.sin2.slickvpn.com.ovpn", country: "Singapore", region: "Asia", city: "Singapore"},
+				"gw1.sjc2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.sjc2.slickvpn.com.ovpn", country: "United States", region: "North America", city: "San Jose"},
+				"gw1.skg1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.skg1.slickvpn.com.ovpn", country: "Greece", region: "Europe", city: "Thessaloniki"},
+				"gw1.sou1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.sou1.slickvpn.com.ovpn", country: "United Kingdom", region: "Europe", city: "Eastleigh near Southampton"},
+				"gw1.stl1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.stl1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "St Louis"},
+				"gw1.svo1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.svo1.slickvpn.com.ovpn", country: "Russian Federation", region: "Europe", city: "Moscow"},
+				"gw1.svo2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.svo2.slickvpn.com.ovpn", country: "Russian Federation", region: "Europe", city: "Moscow"},
+				"gw1.syd1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.syd1.slickvpn.com.ovpn", country: "Australia", region: "Oceania", city: "Sydney"},
+				"gw1.syd2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.syd2.slickvpn.com.ovpn", country: "Australia", region: "Oceania", city: "Sydney"},
+				"gw1.tll1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.tll1.slickvpn.com.ovpn", country: "Estonia", region: "Europe", city: "Tallinn"},
+				"gw1.tlv2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.tlv2.slickvpn.com.ovpn", country: "Israel", region: "Asia", city: "Tel Aviv Yafo"},
+				"gw1.tpa1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.tpa1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Tampa"},
+				"gw1.trf1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.trf1.slickvpn.com.ovpn", country: "Norway", region: "Europe", city: "Torp"},
+				"gw1.waw1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.waw1.slickvpn.com.ovpn", country: "Poland", region: "Europe", city: "Warsaw"},
+				"gw1.yei1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.yei1.slickvpn.com.ovpn", country: "Turkey", region: "Asia", city: "Bursa"},
+				"gw1.yul1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.yul1.slickvpn.com.ovpn", country: "Canada", region: "North America", city: "Montreal"},
+				"gw1.yul2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.yul2.slickvpn.com.ovpn", country: "Canada", region: "North America", city: "Montreal"},
+				"gw1.yvr1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.yvr1.slickvpn.com.ovpn", country: "Canada", region: "North America", city: "Vancouver"},
+				"gw1.yyz1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.yyz1.slickvpn.com.ovpn", country: "Canada", region: "North America", city: "Toronto"},
+				"gw1.zrh1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw1.zrh1.slickvpn.com.ovpn", country: "Switzerland", region: "Europe", city: "Zurich"},
+				"gw2.ams3.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.ams3.slickvpn.com.ovpn", country: "Netherlands", region: "Europe", city: "Amsterdam"},
+				"gw2.atl3.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.atl3.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Atlanta"},
+				"gw2.bcn2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.bcn2.slickvpn.com.ovpn", country: "Spain", region: "Europe", city: "Barcelona"},
+				"gw2.clt1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.clt1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Charlotte"},
+				"gw2.dfw3.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.dfw3.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Dallas"},
+				"gw2.ewr1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.ewr1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Newark"},
+				"gw2.fra1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.fra1.slickvpn.com.ovpn", country: "Germany", region: "Europe", city: "Frankfurt"},
+				"gw2.hou1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.hou1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Houston"},
+				"gw2.iad1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.iad1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Washington"},
+				"gw2.lhr2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.lhr2.slickvpn.com.ovpn", country: "United Kingdom", region: "Europe", city: "London"},
+				"gw2.mel1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.mel1.slickvpn.com.ovpn", country: "Australia", region: "Oceania", city: "Melbourne"},
+				"gw2.mia3.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.mia3.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Miami"},
+				"gw2.mia4.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.mia4.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Miami"},
+				"gw2.mxp2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.mxp2.slickvpn.com.ovpn", country: "Italy", region: "Europe", city: "Milan"},
+				"gw2.ord1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.ord1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Chicago"},
+				"gw2.ost2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.ost2.slickvpn.com.ovpn", country: "Belgium", region: "Europe", city: "Ostend"},
+				"gw2.pao1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.pao1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Palo Alto"},
+				"gw2.prg1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.prg1.slickvpn.com.ovpn", country: "Czech Republic", region: "Europe", city: "Prague"},
+				"gw2.pty1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.pty1.slickvpn.com.ovpn", country: "Panama", region: "North America", city: "Panama City"},
+				"gw2.sin2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.sin2.slickvpn.com.ovpn", country: "Singapore", region: "Asia", city: "Singapore"},
+				"gw2.slc1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.slc1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Salt Lake City"},
+				"gw2.syd2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.syd2.slickvpn.com.ovpn", country: "Australia", region: "Oceania", city: "Sydney"},
+				"gw2.tpe1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.tpe1.slickvpn.com.ovpn", country: "Taiwan", region: "Asia", city: "Taipei"},
+				"gw2.yul2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.yul2.slickvpn.com.ovpn", country: "Canada", region: "North America", city: "Montreal"},
+				"gw2.yyz1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw2.yyz1.slickvpn.com.ovpn", country: "Canada", region: "North America", city: "Toronto"},
+				"gw3.dfw3.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw3.dfw3.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Dallas"},
+				"gw3.ewr1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw3.ewr1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Newark"},
+				"gw3.iad1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw3.iad1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Washington"},
+				"gw3.lax3.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw3.lax3.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Los Angeles"},
+				"gw3.lhr1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw3.lhr1.slickvpn.com.ovpn", country: "United Kingdom", region: "Europe", city: "London"},
+				"gw3.lhr2.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw3.lhr2.slickvpn.com.ovpn", country: "United Kingdom", region: "Europe", city: "London"},
+				"gw3.pao1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw3.pao1.slickvpn.com.ovpn", country: "United States", region: "North America", city: "Palo Alto"},
+				"gw3.per1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw3.per1.slickvpn.com.ovpn", country: "Australia", region: "Oceania", city: "Perth"},
+				"gw3.sou1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw3.sou1.slickvpn.com.ovpn", country: "United Kingdom", region: "Europe", city: "Eastleigh near Southampton"},
+				"gw4.lhr1.slickvpn.com": {ovpnURL: "https://www.slickvpn.com/wp-content/themes/slickvpn-theme/vpn-configs/ovpn/gw4.lhr1.slickvpn.com.ovpn", country: "United Kingdom", region: "Europe", city: "London"},
+			},
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			hostToData, err := parseHTML(testCase.rootNode)
+
+			assert.Equal(t, testCase.hostToData, hostToData)
+			assert.ErrorIs(t, err, testCase.errWrapped)
+			if testCase.errWrapped != nil {
+				assert.EqualError(t, err, testCase.errMessage)
+			}
+		})
+	}
+}

internal/updater/html/attribute.go

@@ -0,0 +1,12 @@
+package html
+
+import "golang.org/x/net/html"
+
+func Attribute(node *html.Node, key string) (value string) {
+	for _, attribute := range node.Attr {
+		if attribute.Key == key {
+			return attribute.Val
+		}
+	}
+	return ""
+}

internal/updater/html/bfs.go

@@ -0,0 +1,43 @@
+package html
+
+import (
+	"container/list"
+	"fmt"
+
+	"golang.org/x/net/html"
+)
+
+// BFS returns the node matching the match function and nil
+// if no node is found.
+func BFS(rootNode *html.Node, match MatchFunc) (node *html.Node) {
+	visited := make(map[*html.Node]struct{})
+	queue := list.New()
+	_ = queue.PushBack(rootNode)
+
+	for queue.Len() > 0 {
+		listElement := queue.Front()
+		node, ok := queue.Remove(listElement).(*html.Node)
+		if !ok {
+			panic(fmt.Sprintf("linked list has bad type %T", listElement.Value))
+		}
+
+		if node == nil {
+			continue
+		}
+
+		if _, ok := visited[node]; ok {
+			continue
+		}
+		visited[node] = struct{}{}
+
+		if match(node) {
+			return node
+		}
+
+		for child := node.FirstChild; child != nil; child = child.NextSibling {
+			_ = queue.PushBack(child)
+		}
+	}
+
+	return nil
+}

internal/updater/html/css.go

@@ -0,0 +1,22 @@
+package html
+
+import (
+	"strings"
+
+	"golang.org/x/net/html"
+)
+
+func HasClassStrings(node *html.Node, classStrings ...string) (match bool) {
+	targetClasses := make(map[string]struct{}, len(classStrings))
+	for _, classString := range classStrings {
+		targetClasses[classString] = struct{}{}
+	}
+
+	classAttribute := Attribute(node, "class")
+	classes := strings.Fields(classAttribute)
+	for _, class := range classes {
+		delete(targetClasses, class)
+	}
+
+	return len(targetClasses) == 0
+}

internal/updater/html/errors.go

@@ -0,0 +1,27 @@
+package html
+
+import (
+	"bytes"
+	"fmt"
+
+	"golang.org/x/net/html"
+)
+
+func WrapError(sentinelError error, node *html.Node) error {
+	return fmt.Errorf("%w: in HTML code: %s",
+		sentinelError, mustRenderHTML(node))
+}
+
+func WrapWarning(warning string, node *html.Node) string {
+	return fmt.Sprintf("%s: in HTML code: %s",
+		warning, mustRenderHTML(node))
+}
+
+func mustRenderHTML(node *html.Node) (rendered string) {
+	stringBuffer := bytes.NewBufferString("")
+	err := html.Render(stringBuffer, node)
+	if err != nil {
+		panic(err)
+	}
+	return stringBuffer.String()
+}

internal/updater/html/match.go

@@ -0,0 +1,43 @@
+package html
+
+import (
+	"golang.org/x/net/html"
+)
+
+type MatchFunc func(node *html.Node) (match bool)
+
+func MatchID(id string) MatchFunc {
+	return func(node *html.Node) (match bool) {
+		if node == nil {
+			return false
+		}
+
+		return Attribute(node, "id") == id
+	}
+}
+
+func MatchData(data string) MatchFunc {
+	return func(node *html.Node) (match bool) {
+		return node != nil && node.Type == html.ElementNode && node.Data == data
+	}
+}
+
+func DirectChild(parent *html.Node,
+	matchFunc MatchFunc) (child *html.Node) {
+	for child := parent.FirstChild; child != nil; child = child.NextSibling {
+		if matchFunc(child) {
+			return child
+		}
+	}
+	return nil
+}
+
+func DirectChildren(parent *html.Node,
+	matchFunc MatchFunc) (children []*html.Node) {
+	for child := parent.FirstChild; child != nil; child = child.NextSibling {
+		if matchFunc(child) {
+			children = append(children, child)
+		}
+	}
+	return children
+}

internal/updater/openvpn/extract.go

@@ -76,6 +76,7 @@ func ExtractIPs(b []byte) (ips []net.IP, err error) {
 func extractRemoteHosts(content []byte, rejectIP, rejectDomain bool) (hosts []string) {
 	lines := strings.Split(string(content), "\n")
 	for _, line := range lines {
+		line = strings.TrimSpace(line)
 		if !strings.HasPrefix(line, "remote ") {
 			continue
 		}

internal/updater/openvpn/multifetch.go

@@ -8,8 +8,8 @@ import (
 // FetchMultiFiles fetches multiple Openvpn files in parallel and
 // parses them to extract each of their host. A mapping from host to
 // URL is returned.
-func FetchMultiFiles(ctx context.Context, client *http.Client, urls []string) (
-	hostToURL map[string]string, err error) {
+func FetchMultiFiles(ctx context.Context, client *http.Client, urls []string,
+	failEarly bool) (hostToURL map[string]string, errors []error) {
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
@@ -22,14 +22,14 @@ func FetchMultiFiles(ctx context.Context, client *http.Client, urls []string) (
 
 	results := make(chan Result)
 	defer close(results)
-	errors := make(chan error)
-	defer close(errors)
+	errorsCh := make(chan error)
+	defer close(errorsCh)
 
 	for _, url := range urls {
 		go func(url string) {
 			host, err := FetchFile(ctx, client, url)
 			if err != nil {
-				errors <- err
+				errorsCh <- err
 				return
 			}
 			results <- Result{
@@ -41,19 +41,26 @@ func FetchMultiFiles(ctx context.Context, client *http.Client, urls []string) (
 
 	for range urls {
 		select {
-		case newErr := <-errors:
-			if err == nil { // only assign to the first error
-				err = newErr
-				cancel() // stop other operations, this will trigger other errors we ignore
-			}
 		case result := <-results:
 			hostToURL[result.host] = result.url
+		case err := <-errorsCh:
+			if !failEarly {
+				errors = append(errors, err)
+				break
+			}
+
+			if len(errors) == 0 {
+				errors = []error{err} // keep only the first error
+				// stop other operations, this will trigger other errors we ignore
+				cancel()
+			}
 		}
 	}
 
-	if err != nil {
-		return nil, err
+	if len(errors) > 0 && failEarly {
+		// we don't care about the result found
+		return nil, errors
 	}
 
-	return hostToURL, nil
+	return hostToURL, errors
 }