使用FCM服务

1.建谷歌账号

2.在console上新建应用 https://console.firebase.google.com 并下载私钥.json

3.创建测试网页应用（或app应用）

C#服务端：

用HTTP v1 API 的方式获取OAuth2的验证，然后再发http请求到FCM发送消息通知。

1.获取Token

 1 public async Task<string> GetTokenAsync(string filePath)
 2         {
 3             var token = _redisDBManager.GetValue(filePath);
 4             if (token != null)
 5                 return token;
 6 
 7             try
 8             {
 9                 GoogleCredential credential = null;
10                 using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read))
11                 {
12                     credential = GoogleCredential.FromStream(stream)
13                         .CreateScoped(@"https://www.googleapis.com/auth/firebase.messaging");
14                 }
15                 var result = await credential.UnderlyingCredential.GetAccessTokenForRequestAsync().ConfigureAwait(false);
16 
17                 _redisDBManager.SetValue(filePath, result, TimeSpan.FromMinutes(50));
18 
19                 return result;
20             }
21             catch (Exception e)
22             {
23                 Logger.LogError($"FCMManager getTokenAsync error, filePath = {filePath}", e);
24                 return null;
25             }
26         }

2.从json解析ProjectId

 1 private static string GetProjectId(string serviceAccountKeyFile)
 2         {
 3             var serviceAccountKeyJson = File.ReadAllText(serviceAccountKeyFile);
 4             var serviceAccountKeyDictionary = JsonConvert.DeserializeObject<Dictionary<string, string>>(serviceAccountKeyJson);
 5 
 6             if (!serviceAccountKeyDictionary.ContainsKey("project_id"))
 7             {
 8                 throw new Exception($"Could not read Project ID from ServiceAccountKey File '{serviceAccountKeyFile}'");
 9             }
10 
11             return serviceAccountKeyDictionary["project_id"];
12         }

3.发送消息

 1 public async Task<AcceptorNoticeInfo> SendAsync(FcmMessage message, string filePath)
 2         {
 3             try
 4             {
 5                 var token = await GetTokenAsync(filePath).ConfigureAwait(false);
 6                 if (token == null)
 7                 {
 8                     _redisDBManager.Remove(filePath);
 9                     token = await GetTokenAsync(filePath).ConfigureAwait(false);
10                 }
11 
12                 var httpClient = new HttpClient();
13                 httpClient.DefaultRequestHeaders
14                     .Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
15                 httpClient.DefaultRequestHeaders.TryAddWithoutValidation("Authorization", $"Bearer {token}");
16 
17                 StringContent content = new StringContent(JsonConvert.SerializeObject(message, new JsonSerializerSettings()
18                 {
19                     NullValueHandling = NullValueHandling.Ignore
20                 }));
21                 var projectId = GetProjectId(filePath);
22                 var url = $"https://fcm.googleapis.com/v1/projects/{projectId}/messages:send";
23 
24                 var responseMessage = await httpClient.PostAsync(url, content)
25                     .ConfigureAwait(false);
26 
27                 if (responseMessage.StatusCode == HttpStatusCode.OK)
28                 {31                     return new AcceptorNoticeInfo()
32                     {
33                         ErrorCode = (int)NoticeError.Success,
34                         ErrorMessage = NoticeError.Success.ToString()
35                     };
36                 }
37                 else
38                 {
39                     var responseContent = await responseMessage.Content.ReadAsStringAsync().ConfigureAwait(false);
40                     var error = JsonConvert.DeserializeObject<FcmMessageErrorResponse>(responseContent);
41                     return new AcceptorNoticeInfo()
42                     {
43                         ErrorCode = (int)responseMessage.StatusCode,
44                         ErrorMessage = error.Error["message"].ToString()
45                     };
46                 }
47             }
48             catch (Exception ex)
49             {
50                 Logger.LogError($"FCM SendAsync error. token = {message.Message.Token}, topic = {message.Message.Token}{message.Message.Condition}", ex);
51                 return new AcceptorNoticeInfo()
52                 {
53                     ErrorCode = (int)NoticeError.Failed,
54                     ErrorMessage = NoticeError.Failed.ToString()
55                 };
56             }
57             
58 
59         }