Philiprehberger.JsonPatch

RFC 6902 JSON Patch operations for System.Text.Json — apply, generate, and parse patch documents.

Installation

dotnet add package Philiprehberger.JsonPatch

Usage

using System.Text.Json.Nodes;
using Philiprehberger.JsonPatch;

var document = JsonNode.Parse("""{"name": "Alice", "age": 30}""");

var operations = new[]
{
    PatchOperation.Replace("/name", JsonValue.Create("Bob")),
    PatchOperation.Add("/email", JsonValue.Create("bob@example.com")),
    PatchOperation.Remove("/age")
};

var result = JsonPatch.Apply(document, operations);
// {"name":"Bob","email":"bob@example.com"}

Generate a Diff

using System.Text.Json.Nodes;
using Philiprehberger.JsonPatch;

var before = JsonNode.Parse("""{"name": "Alice", "age": 30}""");
var after = JsonNode.Parse("""{"name": "Alice", "age": 31, "email": "alice@example.com"}""");

var operations = JsonPatch.Diff(before, after);

foreach (var op in operations)
    Console.WriteLine($"{op.Op} {op.Path}");
// replace /age
// add /email

Parse from JSON

using Philiprehberger.JsonPatch;

var json = """
[
  { "op": "replace", "path": "/name", "value": "Bob" },
  { "op": "remove", "path": "/age" }
]
""";

var patchDoc = JsonPatch.Parse(json);
var result = patchDoc.Apply(JsonNode.Parse("""{"name": "Alice", "age": 30}"""));
// {"name":"Bob"}

Reverse Patch Generation

using System.Text.Json.Nodes;
using Philiprehberger.JsonPatch;

var original = JsonNode.Parse("""{"name": "Alice", "age": 30}""");
var patch = new JsonPatchDocument(new[]
{
    PatchOperation.Replace("/name", JsonValue.Create("Bob")),
    PatchOperation.Remove("/age")
});

var patched = patch.Apply(original);
var reverse = JsonPatch.GenerateReverse(patch, JsonNode.Parse("""{"name": "Alice", "age": 30}"""));
var restored = reverse.Apply(patched);
// restored = {"name":"Alice","age":30}

Patch Validation

using System.Text.Json.Nodes;
using Philiprehberger.JsonPatch;

var document = JsonNode.Parse("""{"name": "Alice"}""");
var patch = new JsonPatchDocument(new[]
{
    PatchOperation.Remove("/nonexistent")
});

var result = JsonPatch.Validate(patch, document);
// result.IsValid == false
// result.Errors[0].Message contains "does not exist"

Patch Composition

using System.Text.Json.Nodes;
using Philiprehberger.JsonPatch;

var first = new JsonPatchDocument(new[]
{
    PatchOperation.Replace("/name", JsonValue.Create("Bob"))
});
var second = new JsonPatchDocument(new[]
{
    PatchOperation.Add("/email", JsonValue.Create("bob@example.com"))
});

var composed = JsonPatch.Compose(first, second);
var result = composed.Apply(JsonNode.Parse("""{"name": "Alice"}"""));
// {"name":"Bob","email":"bob@example.com"}

Partial Application

using System.Text.Json.Nodes;
using Philiprehberger.JsonPatch;

var document = JsonNode.Parse("""{"name": "Alice"}""");
var patch = new JsonPatchDocument(new[]
{
    PatchOperation.Replace("/name", JsonValue.Create("Bob")),
    PatchOperation.Remove("/nonexistent"),
    PatchOperation.Add("/age", JsonValue.Create(30))
});

var result = JsonPatch.ApplyPartial(patch, document);
// result.IsFullyApplied == false
// result.Applied.Count == 2
// result.Failures.Count == 1
// result.Document = {"name":"Bob","age":30}

API

JsonPatch

Method	Description
Apply(JsonNode?, IEnumerable<PatchOperation>)	Apply patch operations to a document, returning a modified copy
Diff(JsonNode?, JsonNode?)	Generate patch operations that transform one document into another
Parse(string)	Parse a JSON array of RFC 6902 operations into a JsonPatchDocument
GenerateReverse(JsonPatchDocument, JsonNode?)	Generate a reverse patch that undoes the given forward patch
Validate(JsonPatchDocument, JsonNode?)	Pre-check whether a patch can be cleanly applied to a document
Compose(JsonPatchDocument, JsonPatchDocument)	Merge two patches into a single equivalent patch
ApplyPartial(JsonPatchDocument, JsonNode?)	Apply operations individually, collecting successes and failures

JsonPatchDocument

Member	Description
JsonPatchDocument(IEnumerable<PatchOperation>)	Create a patch document from a sequence of operations
Operations	Read-only list of patch operations
Apply(JsonNode?)	Apply all operations to a document copy

PatchOperation

Member	Description
Op	Operation type (add, remove, replace, move, copy, test)
Path	Target JSON Pointer path
From	Source path for move/copy operations
Value	Value for add/replace/test operations
Add(string, JsonNode?)	Create an add operation
Remove(string)	Create a remove operation
Replace(string, JsonNode?)	Create a replace operation
Move(string, string)	Create a move operation
Copy(string, string)	Create a copy operation
Test(string, JsonNode?)	Create a test operation

ValidationResult

Member	Description
IsValid	Whether the patch can be cleanly applied without errors
Errors	List of validation errors encountered

ValidationError

Member	Description
Operation	The patch operation that failed validation
Message	Description of why the operation would fail

PartialApplicationResult

Member	Description
Document	The document after applying all successful operations
Applied	Operations that were successfully applied
Failures	Operations that failed with their error messages
IsFullyApplied	Whether all operations were successfully applied

OperationFailure

Member	Description
Operation	The patch operation that failed
Error	Error message describing why the operation failed

Development

dotnet build src/Philiprehberger.JsonPatch.csproj --configuration Release

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License

MIT