1 files changed, 68 insertions, 0 deletions
diff --git a/auth/auth.go b/auth/auth.go
new file mode 100644
index 0000000..c4a67e3
--- /dev/null
+++ b/auth/auth.go
@@ -0,0 +1,68 @@
+package auth
+
+import (
+    "net/http"
+    "fmt"
+    "code.google.com/p/goauth2/oauth"
+    "../util"
+)
+
+// Get auth code from user
+func promptUserForAuthCode(config *oauth.Config) string {
+    authUrl := config.AuthCodeURL("state")
+    fmt.Println("Go to the following link in your browser:")
+    fmt.Printf("%v\n\n", authUrl)
+    return util.Prompt("Enter verification code: ")
+}
+
+// Returns true if we have a valid cached token
+func hasValidToken(cacheFile oauth.CacheFile, transport *oauth.Transport) bool {
+    // Check if we have a cached token
+    token, err := cacheFile.Token()
+    if err != nil {
+        return false
+    }
+
+    // Refresh token if its expired
+    if token.Expired() {
+        transport.Token = token
+        err = transport.Refresh()
+        if err != nil {
+            fmt.Println(err)
+            return false
+        }
+    }
+    return true
+}
+
+func GetOauth2Client(clientId, clientSecret, cachePath string) (*http.Client, error) {
+    cacheFile := oauth.CacheFile(cachePath)
+
+    config := &oauth.Config{
+        ClientId:     clientId,
+        ClientSecret: clientSecret,
+        Scope:        "https://www.googleapis.com/auth/drive",
+        RedirectURL:  "urn:ietf:wg:oauth:2.0:oob",
+        AuthURL:      "https://accounts.google.com/o/oauth2/auth",
+        TokenURL:     "https://accounts.google.com/o/oauth2/token",
+        TokenCache:   cacheFile,
+    }
+
+    transport := &oauth.Transport{
+        Config:    config,
+        Transport: http.DefaultTransport,
+    }
+
+    // Return client if we have a valid token
+    if hasValidToken(cacheFile, transport) {
+        return transport.Client(), nil
+    }
+
+    // Get auth code from user and request a new token
+    code := promptUserForAuthCode(config)
+    _, err := transport.Exchange(code)
+    if err != nil {
+        return nil, err
+    }
+    return transport.Client(), nil
+}