微信三方平台开发上传base64格式图片至临时素材

 1   public string UploadImgByB64(string b64)

 2         {

 3             //access_token 需要自己获取

 4             string access_token = getToken();

 5             string url = $"https://api.weixin.qq.com/cgi-bin/media/upload?access_token={access_token}&type=image";

 6             byte[] data = Convert.FromBase64String(b64);

 7             var boundary = "fbce142e-4e8e-4bf3-826d-cc3cf506cccc";

 8             var client = new HttpClient();

 9             client.DefaultRequestHeaders.Add("User-Agent", "KnowledgeCenter");

10             client.DefaultRequestHeaders.Remove("Expect");

11             client.DefaultRequestHeaders.Remove("Connection");

12             client.DefaultRequestHeaders.ExpectContinue = false;

13             client.DefaultRequestHeaders.ConnectionClose = true;

14             var content = new MultipartFormDataContent(boundary);

15             content.Headers.Remove("Content-Type");

16             content.Headers.TryAddWithoutValidation("Content-Type", "multipart/form-data; boundary=" + boundary);

17             var contentByte = new ByteArrayContent(data);

18             content.Add(contentByte);

19             contentByte.Headers.Remove("Content-Disposition");

20             contentByte.Headers.TryAddWithoutValidation("Content-Disposition", $"form-data; name=\"media\";filename=\"{Guid.NewGuid()}.png\"" + "");

21             contentByte.Headers.Remove("Content-Type");

22             contentByte.Headers.TryAddWithoutValidation("Content-Type", "image/png");

23             try

24             {

25                 var result2 = client.PostAsync(url, content);

26                 if (result2.Result.StatusCode != HttpStatusCode.OK)

27                     throw new Exception(result2.Result.Content.ReadAsStringAsync().Result);

28                 string jsonstr = result2.Result.Content.ReadAsStringAsync().Result;

29                 var dic = Newtonsoft.Json.Linq.JObject.Parse(jsonstr);

30                 return dic["media_id"].ToString();

31             }

32             catch (Exception ex)

33             {

34                 return null;

35             }

36         }