Add --existing option to set subcommand to only set a value if that key is already present

Author: sleeuwen

README.md

@@ -61,6 +61,7 @@ dotnet json set <file> <key> <value> [-o|--output <output file>]
 
 **Options:**
 - _-o|--output file_ Write the result to a custom output file instead of using the input file
+- _-e|--existing_ Only set the value if the key already exists in the json file, otherwise do nothing
 
 ### remove
 

dotnet-json.Tests/Commands/SetCommandTests.cs

@@ -43,6 +43,36 @@ public async Task SavesNewValueToFile(string json, string key, string value)
             result.Should().Be(value);
         }
 
+        [Fact]
+        public async Task Existing_DoesNotChangeFileIfKeyDoesNotExist()
+        {
+            var json = @"{""key1"":""value""}";
+            var filename = Path.Join(_tmpDir, "test.json");
+            await File.WriteAllTextAsync(filename, json);
+
+            var (exitCode, output) = await RunCommand(filename, "key2", "newvalue", "--compressed", "--existing");
+
+            exitCode.Should().Be(0);
+
+            var contents = await File.ReadAllTextAsync(filename);
+            contents.Should().Be(json);
+        }
+
+        [Fact]
+        public async Task Existing_UpdatesValueIfKeyDoesExist()
+        {
+            var json = @"{""key1"":""value"",""key2"":""value""}";
+            var filename = Path.Join(_tmpDir, "test.json");
+            await File.WriteAllTextAsync(filename, json);
+
+            var (exitCode, output) = await RunCommand(filename, "key2", "newvalue", "--compressed", "--existing");
+
+            exitCode.Should().Be(0);
+
+            var contents = await File.ReadAllTextAsync(filename);
+            contents.Should().Be(@"{""key1"":""value"",""key2"":""newvalue""}");
+        }
+
         private async Task<(int exitCode, IConsole console)> RunCommand(params string[] arguments)
         {
             var command = new SetCommand();

dotnet-json/Commands/MergeCommand.cs

@@ -13,6 +13,7 @@ public class MergeCommand : CommandBase
         public MergeCommand() : base("merge", "merge two or more json files into one")
         {
             AddArgument(Files);
+            AddOption(Compressed);
 
             Handler = this;
         }

dotnet-json/Commands/RemoveCommand.cs

@@ -22,6 +22,8 @@ public RemoveCommand()
 
             AddAlias("rm");
 
+            AddOption(Compressed);
+
             Handler = this;
         }
 

dotnet-json/Commands/SetCommand.cs

@@ -12,10 +12,14 @@ public class SetCommand : CommandBase, ICommandHandler
 
         private Argument<string> Value = new Argument<string>("value", "The value to set") { Arity = ArgumentArity.ExactlyOne };
 
+        private Option<bool> Existing = new Option<bool>(new[] { "-e", "--existing" }, "Only set the value if the key already exists in the json file, otherwise do nothing");
+
         public SetCommand() : base("set", "set a value in a json file")
         {
             AddArgument(Key);
             AddArgument(Value);
+            AddOption(Existing);
+            AddOption(Compressed);
 
             Handler = this;
         }
@@ -24,12 +28,16 @@ protected override async Task<int> ExecuteAsync()
         {
             var key = GetParameterValue(Key) ?? throw new ArgumentException("Missing argument <key>");
             var value = GetParameterValue(Value) ?? throw new ArgumentException("Missing argument <value>");
+            var existing = Context!.ParseResult.GetValueForOption(Existing);
 
             JsonDocument document;
 
             await using (var inputStream = GetInputStream())
                 document = JsonDocument.ReadFromStream(inputStream);
 
+            if (existing && document[key] == null)
+                return 0;
+
             document[key] = value;
 
             await using (var outputStream = GetOutputStream())

dotnet-json/dotnet-json.csproj

@@ -14,7 +14,7 @@
     <ToolCommandName>dotnet-json</ToolCommandName>
     <PackageOutputPath>./nupkg</PackageOutputPath>
 
-    <Version>1.0.2</Version>
+    <Version>1.1.0</Version>
     <PackageId>dotnet-json</PackageId>
     <Authors>sleeuwen</Authors>
     <RepositoryUrl>https://github.com/sleeuwen/dotnet-json</RepositoryUrl>