Simplify drive wrapper, s/client/auth/

3 files changed, 119 insertions, 0 deletions

diff --git a/auth/oauth.go b/auth/oauth.go
new file mode 100644
index 0000000..b8f1d47
--- /dev/null
+++ b/auth/oauth.go
@@ -0,0 +1,40 @@
+package auth
+
+import (
+    "net/http"
+    "golang.org/x/oauth2"
+)
+
+type authCodeFn func(string) func() string
+
+func NewOauthClient(clientId, clientSecret, tokenFile string, authFn authCodeFn) (*http.Client, error) {
+    conf := &oauth2.Config{
+        ClientID:     clientId,
+        ClientSecret: clientSecret,
+        Scopes:       []string{"https://www.googleapis.com/auth/drive"},
+        RedirectURL:  "urn:ietf:wg:oauth:2.0:oob",
+        Endpoint: oauth2.Endpoint{
+            AuthURL:  "https://accounts.google.com/o/oauth2/auth",
+            TokenURL: "https://accounts.google.com/o/oauth2/token",
+        },
+    }
+
+    // Read cached token
+    token, exists, err := ReadToken(tokenFile)
+    if err != nil {
+        return nil, err
+    }
+
+    // Require auth code if token file does not exist
+    // or refresh token is missing
+    if !exists || token.RefreshToken == "" {
+        authUrl := conf.AuthCodeURL("state", oauth2.AccessTypeOffline)
+        authCode := authFn(authUrl)()
+        token, err = conf.Exchange(oauth2.NoContext, authCode)
+    }
+
+    return oauth2.NewClient(
+        oauth2.NoContext,
+        FileSource(tokenFile, token, conf),
+    ), nil
+}
diff --git a/auth/token.go b/auth/token.go
new file mode 100644
index 0000000..926d9f6
--- /dev/null
+++ b/auth/token.go
@@ -0,0 +1,57 @@
+package auth
+
+import (
+    "golang.org/x/oauth2"
+    "encoding/json"
+    "io/ioutil"
+)
+
+
+func FileSource(path string, token *oauth2.Token, conf *oauth2.Config) oauth2.TokenSource {
+    return &fileSource{
+        tokenPath: path,
+        tokenSource: conf.TokenSource(oauth2.NoContext, token),
+    }
+}
+
+type fileSource struct {
+    tokenPath string
+    tokenSource oauth2.TokenSource
+}
+
+func (self *fileSource) Token() (*oauth2.Token, error) {
+    token, err := self.tokenSource.Token()
+    if err != nil {
+        return token, err
+    }
+
+    // Save token to file
+    SaveToken(self.tokenPath, token)
+
+    return token, nil
+}
+
+func ReadToken(path string) (*oauth2.Token, bool, error) {
+    if !fileExists(path) {
+        return nil, false, nil
+    }
+
+    content, err := ioutil.ReadFile(path)
+    if err != nil {
+        return nil, true, err
+    }
+    token := &oauth2.Token{}
+    return token, true, json.Unmarshal(content, token)
+}
+
+func SaveToken(path string, token *oauth2.Token) error {
+    data, err := json.MarshalIndent(token, "", "  ")
+    if err != nil {
+        return err
+    }
+
+    if err = mkdir(path); err != nil {
+        return err
+    }
+    return ioutil.WriteFile(path, data, 0600)
+}
diff --git a/auth/util.go b/auth/util.go
new file mode 100644
index 0000000..b053c1f
--- /dev/null
+++ b/auth/util.go
@@ -0,0 +1,22 @@
+package auth
+
+import (
+    "os"
+    "path/filepath"
+)
+
+func mkdir(path string) error {
+    dir := filepath.Dir(path)
+    if fileExists(dir) {
+        return nil
+    }
+    return os.Mkdir(dir, 0700)
+}
+
+func fileExists(path string) bool {
+    _, err := os.Stat(path)
+    if err == nil {
+        return true
+    }
+    return false
+}