Code examples
This chapter contains code examples that use the API
Go command line client
The following is an example in the repository. It is a command line client with the following flags
-get-custom string
The url of a custom server to connect to
-get-institute string
The url of an institute to connect to
-get-secure string
Gets secure internet servers
// Package main implements an example CLI client
package main
import (
"context"
"flag"
"fmt"
"os"
"reflect"
"strings"
"github.com/eduvpn/eduvpn-common/client"
"github.com/eduvpn/eduvpn-common/internal/version"
"github.com/eduvpn/eduvpn-common/types/cookie"
srvtypes "github.com/eduvpn/eduvpn-common/types/server"
"github.com/pkg/browser"
)
// Open a browser with xdg-open.
func openBrowser(data interface{}) {
str, ok := data.(string)
if !ok {
return
}
fmt.Printf("OAuth: Authorization URL: %s\n", str)
fmt.Println("Opening browser...")
go func() {
err := browser.OpenURL(str)
if err != nil {
fmt.Fprintln(os.Stderr, "failed to open browser with error:", err)
fmt.Println("Please open your browser manually")
}
}()
}
// GetLanguageMatched uses a map from language tags to strings to extract the right language given the tag
// It implements it according to https://github.com/eduvpn/documentation/blob/dc4d53c47dd7a69e95d6650eec408e16eaa814a2/SERVER_DISCOVERY.md#language-matching
func GetLanguageMatched(langMap map[string]string, langTag string) string {
// If no map is given, return the empty string
if len(langMap) == 0 {
return ""
}
// Try to find the exact match
if val, ok := langMap[langTag]; ok {
return val
}
// Try to find a key that starts with the OS language setting
for k := range langMap {
if strings.HasPrefix(k, langTag) {
return langMap[k]
}
}
// Try to find a key that starts with the first part of the OS language (e.g. de-)
pts := strings.Split(langTag, "-")
// We have a "-"
if len(pts) > 1 {
for k := range langMap {
if strings.HasPrefix(k, pts[0]+"-") {
return langMap[k]
}
}
}
// search for just the language (e.g. de)
for k := range langMap {
if k == pts[0] {
return langMap[k]
}
}
// Pick one that is deemed best, e.g. en-US or en, but note that not all languages are always available!
// We force an entry that is english exactly or with an english prefix
for k := range langMap {
if k == "en" || strings.HasPrefix(k, "en-") {
return langMap[k]
}
}
// Otherwise just return one
for k := range langMap {
return langMap[k]
}
return ""
}
// Ask for a profile in the command line.
func sendProfile(state *client.Client, data interface{}) {
fmt.Printf("Multiple VPN profiles found. Please select a profile by entering e.g. 1")
d, ok := data.(*srvtypes.RequiredAskTransition)
if !ok {
fmt.Fprintf(os.Stderr, "\ninvalid data type: %v\n", reflect.TypeOf(data))
return
}
sps, ok := d.Data.(*srvtypes.Profiles)
if !ok {
fmt.Fprintf(os.Stderr, "\ninvalid data type for profiles: %v\n", reflect.TypeOf(d.Data))
return
}
ps := ""
var options []string
i := 0
for k, v := range sps.Map {
ps += fmt.Sprintf("\n%d - %s", i+1, GetLanguageMatched(v.DisplayName, "en"))
options = append(options, k)
i++
}
// Show the profiles
fmt.Println(ps)
var idx int
if _, err := fmt.Scanf("%d", &idx); err != nil || idx <= 0 ||
idx > len(sps.Map) {
fmt.Fprintln(os.Stderr, "invalid profile chosen, please retry")
sendProfile(state, data)
return
}
p := options[idx-1]
fmt.Println("Sending profile ID", p)
if err := d.C.Send(p); err != nil {
fmt.Fprintln(os.Stderr, "failed setting profile with error", err)
}
}
// The callback function
// If OAuth is started we open the browser with the Auth URL
// If we ask for a profile, we send the profile using command line input
// Note that this has an additional argument, the vpn state which was wrapped into this callback function below.
func stateCallback(state *client.Client, _ client.FSMStateID, newState client.FSMStateID, data interface{}) {
if newState == client.StateOAuthStarted {
openBrowser(data)
}
if newState == client.StateAskProfile {
sendProfile(state, data)
}
}
// Get a config for Institute Access or Secure Internet Server.
func getConfig(state *client.Client, url string, srvType srvtypes.Type) (*srvtypes.Configuration, error) {
if !strings.HasPrefix(url, "http") {
url = "https://" + url
}
ck := cookie.NewWithContext(context.Background())
defer ck.Cancel() //nolint:errcheck
err := state.AddServer(ck, url, srvType, nil)
if err != nil {
return nil, err
}
return state.GetConfig(ck, url, srvType, false, false)
}
// Get a config for a single server, Institute Access or Secure Internet.
func printConfig(url string, srvType srvtypes.Type) {
var c *client.Client
c, err := client.New(
"org.eduvpn.app.linux",
fmt.Sprintf("%s-cli", version.Version),
"configs",
func(old client.FSMStateID, new client.FSMStateID, data interface{}) bool {
stateCallback(c, old, new, data)
return true
},
true,
)
if err != nil {
fmt.Printf("Register error: %v", err)
return
}
_ = c.Register()
ck := cookie.NewWithContext(context.Background())
_, err = c.DiscoOrganizations(ck, "")
if err != nil {
panic(err)
}
_, err = c.DiscoServers(ck, "")
if err != nil {
panic(err)
}
defer c.Deregister()
cfg, err := getConfig(c, url, srvType)
if err != nil {
fmt.Fprintf(os.Stderr, "failed getting a config: %v\n", err)
return
}
fmt.Println(cfg.Protocol)
fmt.Println("Obtained config:", cfg.VPNConfig)
}
// The main function
// It parses the arguments and executes the correct functions.
func main() {
cu := flag.String("get-custom", "", "The url of a custom server to connect to")
u := flag.String("get-institute", "", "The url of an institute to connect to")
sec := flag.String("get-secure", "", "Gets secure internet servers")
flag.Parse()
// Connect to a VPN by getting an Institute Access config
switch {
case *cu != "":
printConfig(*cu, srvtypes.TypeCustom)
case *u != "":
printConfig(*u, srvtypes.TypeInstituteAccess)
case *sec != "":
printConfig(*sec, srvtypes.TypeSecureInternet)
default:
flag.PrintDefaults()
}
}