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◆ patch()
template<template< typename U, typename V, typename... Args > class ObjectType = std::map, template< typename U, typename... Args > class ArrayType = std::vector, class StringType = std::string, class BooleanType = bool, class NumberIntegerType = std::int64_t, class NumberUnsignedType = std::uint64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator, template< typename T, typename SFINAE=void > class JSONSerializer = adl_serializer>
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"} 27 json patched_doc = doc.patch(patch); 30 std::cout << std::setw(4) << doc << "\n\n" 31 << std::setw(4) << patched_doc << std::endl; basic_json<> json default JSON class
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 19798 of file json.hpp.
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