feat: check if a file exists

Author: cnblogs-dudu

src/GitLabApiClient/FilesClient.cs

@@ -1,4 +1,6 @@
+using System.Net;
 using System.Threading.Tasks;
+
 using GitLabApiClient.Internal.Http;
 using GitLabApiClient.Internal.Paths;
 using GitLabApiClient.Internal.Utilities;
@@ -16,5 +18,16 @@ public async Task<File> GetAsync(ProjectId projectId, string filePath, string re
         {
             return await _httpFacade.Get<File>($"projects/{projectId}/repository/files/{filePath.UrlEncode()}?ref={reference}");
         }
+
+        public async Task<bool> ExistsAsync(ProjectId projectId, string filePath, string reference = "master")
+        {
+            var response = await _httpFacade.Head($"projects/{projectId}/repository/files/{filePath.UrlEncode()}?ref={reference}");
+            return response.StatusCode switch
+            {
+                HttpStatusCode.OK => true,
+                HttpStatusCode.NotFound => false,
+                _ => throw new GitLabException(response.StatusCode, "")
+            };
+        }
     }
 }

src/GitLabApiClient/GitLabApiClient.csproj

@@ -16,6 +16,7 @@
     <IncludeSymbols>true</IncludeSymbols>
     <UseFullSemVerForNuGet>true</UseFullSemVerForNuGet>
     <SymbolPackageFormat>snupkg</SymbolPackageFormat>
+    <LangVersion>latest</LangVersion>
   </PropertyGroup>
 
   <PropertyGroup Condition=" '$(GITHUB_ACTIONS)' == 'true'">

src/GitLabApiClient/IFilesClient.cs

@@ -1,4 +1,5 @@
 using System.Threading.Tasks;
+
 using GitLabApiClient.Internal.Paths;
 using GitLabApiClient.Models.Files.Responses;
 
@@ -7,5 +8,6 @@ namespace GitLabApiClient
     public interface IFilesClient
     {
         Task<File> GetAsync(ProjectId projectId, string filePath, string reference = "master");
+        Task<bool> ExistsAsync(ProjectId projectId, string filePath, string reference = "master");
     }
 }

src/GitLabApiClient/Internal/Http/GitLabHttpFacade.cs

@@ -64,6 +64,9 @@ private void Setup(RequestsJsonSerializer jsonSerializer)
             _pagedRequestor = new GitLabApiPagedRequestor(_requestor);
         }
 
+        public Task<HttpResponseMessage> Head(string url) =>
+            _requestor.Head(url);
+
         public Task<IList<T>> GetPagedList<T>(string uri) =>
             _pagedRequestor.GetPagedList<T>(uri);
 

src/GitLabApiClient/Internal/Http/GitlabApiRequestor.cs

@@ -4,6 +4,7 @@
 using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Threading.Tasks;
+
 using GitLabApiClient.Internal.Http.Serialization;
 using GitLabApiClient.Models.Uploads.Requests;
 using GitLabApiClient.Models.Uploads.Responses;
@@ -21,6 +22,12 @@ public GitLabApiRequestor(HttpClient client, RequestsJsonSerializer jsonSerializ
             _jsonSerializer = jsonSerializer;
         }
 
+        public async Task<HttpResponseMessage> Head(string url)
+        {
+            var requestMessage = new HttpRequestMessage(HttpMethod.Head, url);
+            return await _client.SendAsync(requestMessage);
+        }
+
         public async Task<T> Get<T>(string url)
         {
             var responseMessage = await _client.GetAsync(url);