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Niels Lohmann
63c10a51fc
* Review and extend the documentation, and check it in CI A review of all documentation pages found factual errors, dead links, missing cross-references, and gaps in examples. This fixes them and adds checks so the same problems are caught automatically. Fixes: - wrong signatures and version histories (operator!= C++20 member, binary() subtype type, get<PointerType>(), JSON_NO_THREAD_LOCAL, ...) - stale descriptions (number parsing since #5283, UBJSON table, SAX example that no longer compiled, tsl::ordered_map advice) - dead internal and external links; repology.org badges (the domain is suspended) replaced by badges that query the registries directly - deprecation notes link the migration guide; the guide itself fixed Additions: - "See also" sections, cross-references, 25 runnable examples, 12 Mermaid diagrams, new API pages for json_pointer::operator<=> and byte_container_with_subtype::operator==/!= - landing page, guides for untrusted input and performance - "unreleased" badge after versions newer than the latest release Checks: - strict documentation build (broken links/anchors fail it); CI and the publish workflow fetch the full history the build needs - weekly external link check, Mermaid syntax check in CI - check_structure.py: example titles, heading levels, alt texts, header links, docset index coverage; its unused-example check works again - all examples produce the same output on every platform Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Keep the customer links that could not be fixed A dead link on the customers page is still the evidence of where the use of the library was documented. Keep the original URLs of the entries without a working replacement (Marne, Cisco Webex Desk Camera, Philips Hue, CyberArk) and exclude exactly these URLs from the link check. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Correct the duplicate-key recipe's claim about SAX positions The SAX interface's key() receives no position either; only parse_error() does. Also note that the recipe does not report the path to the repeated key (see discussion #5085). Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Say the library is available as a single header and mention json_fwd.hpp Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Correct documentation errors found while hunting for bugs - patch/patch_inplace: list the JSON pointer errors parse_error.106-109 and out_of_range.402/404, and quote the actual parse_error.105 message. - unflatten: list parse_error.106/107/108 and out_of_range.404. - to_bson: list out_of_range.415 (binary subtype above 255) and note that 412 and 415 are new in 3.13.0. - to_string: state that string_t must be convertible to std::string, also in the StringType requirements table. - JSON Lines: a `while (input >> j)` loop also throws after the last value for concatenated JSON values; show a loop that works for both. - BON8: a string gets 0xFF only if nothing follows it in the message; a string at the end of an array or object is ended by 0xFE. - custom_string_type.hpp: add operator+=(char), which the "Always required" list asks for (json_pointer::to_string, flatten, unflatten, and diff did not compile), and an ADL int_to_string for diff and items. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Cache the release headers with functools.lru_cache Codacy (Pylint) flagged the mutable default argument that header() used as its cache. functools.lru_cache keeps the same memoization without it. The script's output is unchanged. Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
3.1 KiB
3.1 KiB
nlohmann::basic_json::to_msgpack
// (1)
static std::vector<std::uint8_t> to_msgpack(const basic_json& j);
// (2)
static void to_msgpack(const basic_json& j, detail::output_adapter<std::uint8_t> o);
static void to_msgpack(const basic_json& j, detail::output_adapter<char> o);
Serializes a given JSON value j to a byte vector using the MessagePack serialization format. MessagePack is a binary
serialization format that aims to be more compact than JSON itself, yet more efficient to parse.
- Returns a byte vector containing the MessagePack serialization.
- Writes the MessagePack serialization to an output adapter.
The exact mapping and its limitations are described on a dedicated page.
Parameters
j(in)- JSON value to serialize
o(in)- output adapter to write serialization to
Return value
- MessagePack serialization as a byte vector
- (none)
Exception safety
Strong guarantee: if an exception is thrown, there are no changes in the JSON value.
Exceptions
- Throws
out_of_range.412if the length of a string, binary value, array, or object exceeds 4294967295, the maximum MessagePack can store; example:"MessagePack length 4294967296 exceeds maximum of 4294967295" - Throws
out_of_range.415if the subtype of a binary value exceeds 255, the maximum of the MessagePack ext type; example:"subtype 70000 is too large for the MessagePack ext type (max 255)"
Complexity
Linear in the size of the JSON value j.
Examples
??? example "Example: serialize a JSON value to MessagePack"
The example shows the serialization of a JSON value to a byte vector in MessagePack format.
```cpp
--8<-- "examples/to_msgpack.cpp"
```
Output:
```json
--8<-- "examples/to_msgpack.output"
```
??? example "Example: out_of_range.415 exception"
The example shows how serializing a binary value whose subtype exceeds 255 throws an exception, because the
MessagePack ext type stores the subtype in a single byte.
```cpp
--8<-- "examples/to_msgpack__exception.cpp"
```
Output:
```json
--8<-- "examples/to_msgpack__exception.output"
```
See also
- from_msgpack create a JSON value from an input in MessagePack format
- to_cbor create a CBOR serialization of a JSON value
- to_bson create a BSON serialization of a JSON value
- to_ubjson create a UBJSON serialization of a JSON value
- to_bjdata create a BJData serialization of a JSON value
- to_bon8 create a BON8 serialization of a JSON value
Version history
- Added in version 2.0.9.
- Throws
out_of_range.412andout_of_range.415since version 3.13.0. - Fixed in version 3.13.0 to serialize
number_integer_t/number_unsigned_tpairs of different width correctly; before, integers could be serialized with the wrong value ifnumber_integer_twas narrower thannumber_unsigned_t.