Implement Yandex storage backend - fixes #234

yandex/api/download.go

@@ -0,0 +1,66 @@
+package src
+
+import (
+	"encoding/json"
+	"io"
+	"net/url"
+)
+
+// DownloadResponse struct is returned by the API for Download request.
+type DownloadResponse struct {
+	HRef      string `json:"href"`
+	Method    string `json:"method"`
+	Templated bool   `json:"templated"`
+}
+
+// Download will get specified data from Yandex.Disk.
+func (c *Client) Download(remotePath string) (io.ReadCloser, error) { //io.Writer
+	ur, err := c.DownloadRequest(remotePath)
+	if err != nil {
+		return nil, err
+	}
+	return c.PerformDownload(ur.HRef)
+}
+
+// DownloadRequest will make an download request and return a URL to download data to.
+func (c *Client) DownloadRequest(remotePath string) (*DownloadResponse, error) {
+	values := url.Values{}
+	values.Add("path", remotePath)
+
+	req, err := c.scopedRequest("GET", "/v1/disk/resources/download?"+values.Encode(), nil)
+	if err != nil {
+		return nil, err
+	}
+
+	resp, err := c.HTTPClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	if err := CheckAPIError(resp); err != nil {
+		return nil, err
+	}
+	defer CheckClose(resp.Body, &err)
+
+	ur, err := ParseDownloadResponse(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	return ur, nil
+}
+
+// ParseDownloadResponse tries to read and parse DownloadResponse struct.
+func ParseDownloadResponse(data io.Reader) (*DownloadResponse, error) {
+	dec := json.NewDecoder(data)
+	var ur DownloadResponse
+
+	if err := dec.Decode(&ur); err == io.EOF {
+		// ok
+	} else if err != nil {
+		return nil, err
+	}
+
+	// TODO: check if there is any trash data after JSON and crash if there is.
+
+	return &ur, nil
+}