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Inada Naoki 2020-12-18 16:13:35 +09:00
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@ -64,9 +64,9 @@ See note below for detail.
## Install ## Install
```
$ pip install msgpack $ pip install msgpack
```
### Pure Python implementation ### Pure Python implementation
@ -103,18 +103,18 @@ msgpack provides `dumps` and `loads` as an alias for compatibility with
`unpack` and `load` unpacks from a file-like object. `unpack` and `load` unpacks from a file-like object.
```pycon ```pycon
>>> import msgpack >>> import msgpack
>>> msgpack.packb([1, 2, 3], use_bin_type=True) >>> msgpack.packb([1, 2, 3], use_bin_type=True)
'\x93\x01\x02\x03' '\x93\x01\x02\x03'
>>> msgpack.unpackb(_, raw=False) >>> msgpack.unpackb(_, raw=False)
[1, 2, 3] [1, 2, 3]
``` ```
`unpack` unpacks msgpack's array to Python's list, but can also unpack to tuple: `unpack` unpacks msgpack's array to Python's list, but can also unpack to tuple:
```pycon ```pycon
>>> msgpack.unpackb(b'\x93\x01\x02\x03', use_list=False, raw=False) >>> msgpack.unpackb(b'\x93\x01\x02\x03', use_list=False, raw=False)
(1, 2, 3) (1, 2, 3)
``` ```
You should always specify the `use_list` keyword argument for backward compatibility. You should always specify the `use_list` keyword argument for backward compatibility.
@ -129,18 +129,18 @@ Read the docstring for other options.
stream (or from bytes provided through its `feed` method). stream (or from bytes provided through its `feed` method).
```py ```py
import msgpack import msgpack
from io import BytesIO from io import BytesIO
buf = BytesIO() buf = BytesIO()
for i in range(100): for i in range(100):
buf.write(msgpack.packb(i, use_bin_type=True)) buf.write(msgpack.packb(i, use_bin_type=True))
buf.seek(0) buf.seek(0)
unpacker = msgpack.Unpacker(buf, raw=False) unpacker = msgpack.Unpacker(buf, raw=False)
for unpacked in unpacker: for unpacked in unpacker:
print(unpacked) print(unpacked)
``` ```
@ -150,27 +150,27 @@ It is also possible to pack/unpack custom data types. Here is an example for
`datetime.datetime`. `datetime.datetime`.
```py ```py
import datetime import datetime
import msgpack import msgpack
useful_dict = { useful_dict = {
"id": 1, "id": 1,
"created": datetime.datetime.now(), "created": datetime.datetime.now(),
} }
def decode_datetime(obj): def decode_datetime(obj):
if '__datetime__' in obj: if '__datetime__' in obj:
obj = datetime.datetime.strptime(obj["as_str"], "%Y%m%dT%H:%M:%S.%f") obj = datetime.datetime.strptime(obj["as_str"], "%Y%m%dT%H:%M:%S.%f")
return obj return obj
def encode_datetime(obj): def encode_datetime(obj):
if isinstance(obj, datetime.datetime): if isinstance(obj, datetime.datetime):
return {'__datetime__': True, 'as_str': obj.strftime("%Y%m%dT%H:%M:%S.%f")} return {'__datetime__': True, 'as_str': obj.strftime("%Y%m%dT%H:%M:%S.%f")}
return obj return obj
packed_dict = msgpack.packb(useful_dict, default=encode_datetime, use_bin_type=True) packed_dict = msgpack.packb(useful_dict, default=encode_datetime, use_bin_type=True)
this_dict_again = msgpack.unpackb(packed_dict, object_hook=decode_datetime, raw=False) this_dict_again = msgpack.unpackb(packed_dict, object_hook=decode_datetime, raw=False)
``` ```
`Unpacker`'s `object_hook` callback receives a dict; the `Unpacker`'s `object_hook` callback receives a dict; the
@ -183,25 +183,25 @@ key-value pairs.
It is also possible to pack/unpack custom data types using the **ext** type. It is also possible to pack/unpack custom data types using the **ext** type.
```pycon ```pycon
>>> import msgpack >>> import msgpack
>>> import array >>> import array
>>> def default(obj): >>> def default(obj):
... if isinstance(obj, array.array) and obj.typecode == 'd': ... if isinstance(obj, array.array) and obj.typecode == 'd':
... return msgpack.ExtType(42, obj.tostring()) ... return msgpack.ExtType(42, obj.tostring())
... raise TypeError("Unknown type: %r" % (obj,)) ... raise TypeError("Unknown type: %r" % (obj,))
... ...
>>> def ext_hook(code, data): >>> def ext_hook(code, data):
... if code == 42: ... if code == 42:
... a = array.array('d') ... a = array.array('d')
... a.fromstring(data) ... a.fromstring(data)
... return a ... return a
... return ExtType(code, data) ... return ExtType(code, data)
... ...
>>> data = array.array('d', [1.2, 3.4]) >>> data = array.array('d', [1.2, 3.4])
>>> packed = msgpack.packb(data, default=default, use_bin_type=True) >>> packed = msgpack.packb(data, default=default, use_bin_type=True)
>>> unpacked = msgpack.unpackb(packed, ext_hook=ext_hook, raw=False) >>> unpacked = msgpack.unpackb(packed, ext_hook=ext_hook, raw=False)
>>> data == unpacked >>> data == unpacked
True True
``` ```
@ -226,11 +226,11 @@ You can pack into and unpack from this old spec using `use_bin_type=False`
and `raw=True` options. and `raw=True` options.
```pycon ```pycon
>>> import msgpack >>> import msgpack
>>> msgpack.unpackb(msgpack.packb([b'spam', u'eggs'], use_bin_type=False), raw=True) >>> msgpack.unpackb(msgpack.packb([b'spam', u'eggs'], use_bin_type=False), raw=True)
[b'spam', b'eggs'] [b'spam', b'eggs']
>>> msgpack.unpackb(msgpack.packb([b'spam', u'eggs'], use_bin_type=True), raw=False) >>> msgpack.unpackb(msgpack.packb([b'spam', u'eggs'], use_bin_type=True), raw=False)
[b'spam', 'eggs'] [b'spam', 'eggs']
``` ```
### ext type ### ext type
@ -238,10 +238,10 @@ and `raw=True` options.
To use the **ext** type, pass `msgpack.ExtType` object to packer. To use the **ext** type, pass `msgpack.ExtType` object to packer.
```pycon ```pycon
>>> import msgpack >>> import msgpack
>>> packed = msgpack.packb(msgpack.ExtType(42, b'xyzzy')) >>> packed = msgpack.packb(msgpack.ExtType(42, b'xyzzy'))
>>> msgpack.unpackb(packed) >>> msgpack.unpackb(packed)
ExtType(code=42, data='xyzzy') ExtType(code=42, data='xyzzy')
``` ```
You can use it with `default` and `ext_hook`. See below. You can use it with `default` and `ext_hook`. See below.