Add GitService.GetBlobRaw method. (#891)

This method is similar to GitService.GetBlob, except it uses the
"application/vnd.github.v3.raw" media type to fetch the blob content
as raw bytes (rather than a JSON object containing a base64-encoded
string and other information).

GitHub API docs:

-	https://developer.github.com/v3/git/blobs/#get-a-blob
-	https://developer.github.com/v3/git/blobs/#custom-media-types

Fixes #658.

Author: dsymonds

github/git_blobs.go

@@ -6,6 +6,7 @@
 package github
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 )
@@ -20,7 +21,7 @@ type Blob struct {
 	NodeID   *string `json:"node_id,omitempty"`
 }
 
-// GetBlob fetchs a blob from a repo given a SHA.
+// GetBlob fetches a blob from a repo given a SHA.
 //
 // GitHub API docs: https://developer.github.com/v3/git/blobs/#get-a-blob
 func (s *GitService) GetBlob(ctx context.Context, owner string, repo string, sha string) (*Blob, *Response, error) {
@@ -38,6 +39,23 @@ func (s *GitService) GetBlob(ctx context.Context, owner string, repo string, sha
 	return blob, resp, err
 }
 
+// GetBlobRaw fetches a blob's contents from a repo.
+// Unlike GetBlob, it returns the raw bytes rather than the base64-encoded data.
+//
+// GitHub API docs: https://developer.github.com/v3/git/blobs/#get-a-blob
+func (s *GitService) GetBlobRaw(ctx context.Context, owner, repo, sha string) ([]byte, *Response, error) {
+	u := fmt.Sprintf("repos/%v/%v/git/blobs/%v", owner, repo, sha)
+	req, err := s.client.NewRequest("GET", u, nil)
+	if err != nil {
+		return nil, nil, err
+	}
+	req.Header.Set("Accept", "application/vnd.github.v3.raw")
+
+	var buf bytes.Buffer
+	resp, err := s.client.Do(ctx, req, &buf)
+	return buf.Bytes(), resp, err
+}
+
 // CreateBlob creates a blob object.
 //
 // GitHub API docs: https://developer.github.com/v3/git/blobs/#create-a-blob

github/git_blobs_test.go

@@ -6,6 +6,7 @@
 package github
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
@@ -51,6 +52,28 @@ func TestGitService_GetBlob_invalidOwner(t *testing.T) {
 	testURLParseError(t, err)
 }
 
+func TestGitService_GetBlobRaw(t *testing.T) {
+	client, mux, _, teardown := setup()
+	defer teardown()
+
+	mux.HandleFunc("/repos/o/r/git/blobs/s", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, "GET")
+		testHeader(t, r, "Accept", "application/vnd.github.v3.raw")
+
+		fmt.Fprint(w, `raw contents here`)
+	})
+
+	blob, _, err := client.Git.GetBlobRaw(context.Background(), "o", "r", "s")
+	if err != nil {
+		t.Errorf("Git.GetBlobRaw returned error: %v", err)
+	}
+
+	want := []byte("raw contents here")
+	if !bytes.Equal(blob, want) {
+		t.Errorf("GetBlobRaw returned %q, want %q", blob, want)
+	}
+}
+
 func TestGitService_CreateBlob(t *testing.T) {
 	client, mux, _, teardown := setup()
 	defer teardown()