check if imgbot branch exists when manually triggering

Auth/InstallationFunction.cs

@@ -5,6 +5,7 @@
 using System.Text.RegularExpressions;
 using System.Threading.Tasks;
 using Auth.Extensions;
+using Common;
 using Microsoft.Azure.WebJobs;
 using Microsoft.Azure.WebJobs.Extensions.Http;
 using Microsoft.WindowsAzure.Storage;
@@ -185,6 +186,17 @@ public static async Task<HttpResponseMessage> RequestRepositoryCheckAsync(
                 throw new Exception("repository request mismatch");
             }
 
+            var response = req.CreateResponse();
+            response.EnableCors();
+
+            var imgbotBranch = await GetImgbotBranch(repository, token);
+            if (imgbotBranch != null)
+            {
+                // branch already exists
+                response.SetJson(new { status = "branchexists" });
+                return response;
+            }
+
             await routerQueue.AddMessageAsync(new CloudQueueMessage(JsonConvert.SerializeObject(new Common.Messages.RouterMessage
             {
                 CloneUrl = repository.html_url,
@@ -193,10 +205,7 @@ await routerQueue.AddMessageAsync(new CloudQueueMessage(JsonConvert.SerializeObj
                 RepoName = repository.name,
             })));
 
-            var response = req.CreateResponse();
-            response
-              .SetJson(new { status = "OK" })
-              .EnableCors();
+            response.SetJson(new { status = "OK" });
             return response;
         }
 
@@ -357,5 +366,29 @@ private static string ParseNextHeader(HttpResponseMessage response)
 
             return repository;
         }
+
+        private static async Task<Model.Branch> GetImgbotBranch(Model.Repository repository, string token)
+        {
+            Model.Branch imgbotBranch = null;
+
+            try
+            {
+                var imgbotBranchRequest = new HttpRequestMessage(HttpMethod.Get, repository.branches_url.Replace("{/branch}", $"/{KnownGitHubs.BranchName}"));
+                imgbotBranchRequest.Headers.Authorization = new AuthenticationHeaderValue("token", token);
+                imgbotBranchRequest.AddGithubHeaders();
+                var imgbotBranchResponse = await HttpClient.SendAsync(imgbotBranchRequest);
+                var imbotBranchJson = await imgbotBranchResponse.Content.ReadAsStringAsync();
+                imgbotBranch = JsonConvert.DeserializeObject<Model.Branch>(imbotBranchJson);
+                if (imgbotBranch.name != KnownGitHubs.BranchName)
+                {
+                    return null;
+                }
+            }
+            catch
+            {
+            }
+
+            return imgbotBranch;
+        }
     }
 }

Auth/Model/Branch.cs

@@ -0,0 +1,11 @@
+// <auto-generated/>
+
+namespace Auth.Model
+{
+    public class Branch
+    {
+        public string name { get; set; }
+        public bool @protected { get; set; }
+        public string protection_url { get; set; }
+    }
+}

Web/src/app/vue/components/Repository.vue

@@ -108,33 +108,39 @@ export default {
       var vm = this;
 
       vm.checking = true;
+
       axios
         .get(
           `${settings.authhost}/api/repositories/check/${vm.installationid}/${vm.current.id}`,
           {
             withCredentials: true
           }
         )
-        .then(() => {
-          var interval = setInterval(() => {
-            axios
-              .get(
-                `${settings.authhost}/api/repositories/${vm.installationid}/repository/${vm.current.id}`,
-                {
-                  withCredentials: true
-                }
-              )
-              .then(response => {
-                if (
-                  vm.current.lastchecked !==
-                  response.data.repository.lastchecked
-                ) {
-                  clearInterval(interval);
-                  vm.current = response.data.repository;
-                  vm.checking = false;
-                }
-              });
-          }, 30000);
+        .then((checkResponse) => {
+          if (checkResponse.data.status === "branchexists") {
+            alert("The Imgbot branch already exists in this repo. If you want a new round of optimization please delete this branch and try again.");
+            vm.checking = false;
+          } else {
+            var interval = setInterval(() => {
+              axios
+                .get(
+                  `${settings.authhost}/api/repositories/${vm.installationid}/repository/${vm.current.id}`,
+                  {
+                    withCredentials: true
+                  }
+                )
+                .then(response => {
+                  if (
+                    vm.current.lastchecked !==
+                    response.data.repository.lastchecked
+                  ) {
+                    clearInterval(interval);
+                    vm.current = response.data.repository;
+                    vm.checking = false;
+                  }
+                });
+            }, 30000);
+          }
         });
     },
     loadSettings: function() {