|
◆ patch()
JSON Patch defines a JSON document structure for expressing a sequence of operations to apply to a JSON) document. With this function, a JSON Patch is applied to the current JSON value by executing all operations from the patch.
- Parameters
-
[in] | json_patch | JSON patch document |
- Returns
- patched document
- Note
- The application of a patch is atomic: Either all operations succeed and the patched document is returned or an exception is thrown. In any case, the original value is not changed: the patch is applied to a copy of the value.
- Exceptions
-
parse_error.104 | if the JSON patch does not consist of an array of objects |
parse_error.105 | if the JSON patch is malformed (e.g., mandatory attributes are missing); example: "operation add must have member path" |
out_of_range.401 | if an array index is out of range. |
out_of_range.403 | if a JSON pointer inside the patch could not be resolved successfully in the current JSON value; example: "key baz not
found" |
out_of_range.405 | if JSON pointer has no parent ("add", "remove", "move") |
other_error.501 | if "test" operation was unsuccessful |
- Complexity
- Linear in the size of the JSON value and the length of the JSON patch. As usually only a fraction of the JSON value is affected by the patch, the complexity can usually be neglected.
- Example
- The following code shows how a JSON patch is applied to a value.
3 #include <nlohmann/json.hpp>
20 { "op": "replace", "path": "/baz", "value": "boo" },
21 { "op": "add", "path": "/hello", "value": ["world"] },
22 { "op": "remove", "path": "/foo"}
30 std::cout << std::setw(4) << doc << "\n\n"
31 << std::setw(4) << patched_doc << std::endl;
Output (play with this example online): {
"baz": "qux",
"foo": "bar"
}
{
"baz": "boo",
"hello": [
"world"
]
}
The example code above can be translated withg++ -std=c++11 -Isingle_include doc/examples/patch.cpp -o patch
- See also
- diff – create a JSON patch by comparing two JSON values
-
RFC 6902 (JSON Patch)
-
RFC 6901 (JSON Pointer)
- Since
- version 2.0.0
Definition at line 22120 of file json.hpp.
|