// Exec executes the given request. Returns a GraphError if the response from Facebook is an error, or just
// a normal error if something goes wrong before that or during unmarshaling.
func (r *GraphRequest) Exec(target interface{}) error {
p := r.Path
if r.Version != Unversioned {
p = "/" + string(r.Version) + "/" + p
}
p = path.Clean(p)
url := url.URL{
Scheme: "https",
Host: "graph.facebook.com",
Path: p,
RawQuery: url.Values(r.Query).Encode(),
}
req, _ := http.NewRequest(string(r.Method), url.String(), nil)
if r.IsJSON {
req.Header.Add("Accept", "application/json")
}
resp, err := r.client.Do(req)
if err != nil {
return fmt.Errorf("error setting up http request: %s", err)
}
buf, err := ioutil.ReadAll(resp.Body)
if err != nil {
return fmt.Errorf("error reading response body")
}
if resp.StatusCode != 200 {
errorTarget := GraphError{}
err = json.Unmarshal(buf, &errorTarget)
if err != nil {
return fmt.Errorf("couldn't unmarshal response into Graph Error: %s\n\t%s", err, string(buf))
}
return errorTarget
}
if _, ok := target.(*[]byte); ok {
*(target.(*[]byte)) = buf
return nil
} else if r.IsJSON {
err = json.Unmarshal(buf, target)
if err != nil {
return fmt.Errorf("error unmarshaling response into %T: %s\n\n%s", target, err, string(buf))
}
} else {
return fmt.Errorf("invalid target type for non-json response: %T", target)
}
return nil
}