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Configurable blocksize in HTTP(S)Connection #76126

nirs mannequin opened this issue Nov 4, 2017 · 5 comments

Configurable blocksize in HTTP(S)Connection #76126

nirs mannequin opened this issue Nov 4, 2017 · 5 comments
3.7 stdlib type-feature


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@nirs nirs mannequin commented Nov 4, 2017

BPO 31945
Nosy @brettcannon, @nirs, @vstinner, @serhiy-storchaka, @1st1
  • #4279
  • Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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    GitHub fields:

    assignee = None
    closed_at = <Date 2017-11-06.21:21:57.942>
    created_at = <Date 2017-11-04.22:32:30.582>
    labels = ['3.7', 'type-feature', 'library']
    title = 'Configurable blocksize in HTTP(S)Connection'
    updated_at = <Date 2017-11-06.21:21:57.941>
    user = '' fields:

    activity = <Date 2017-11-06.21:21:57.941>
    actor = 'vstinner'
    assignee = 'none'
    closed = True
    closed_date = <Date 2017-11-06.21:21:57.942>
    closer = 'vstinner'
    components = ['Library (Lib)']
    creation = <Date 2017-11-04.22:32:30.582>
    creator = 'nirs'
    dependencies = []
    files = []
    hgrepos = []
    issue_num = 31945
    keywords = ['patch']
    message_count = 5.0
    messages = ['305571', '305624', '305678', '305679', '305680']
    nosy_count = 5.0
    nosy_names = ['brett.cannon', 'nirs', 'vstinner', 'serhiy.storchaka', 'yselivanov']
    pr_nums = ['4279']
    priority = 'normal'
    resolution = 'fixed'
    stage = 'resolved'
    status = 'closed'
    superseder = None
    type = 'enhancement'
    url = ''
    versions = ['Python 3.7']

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    Mannequin Author

    @nirs nirs mannequin commented Nov 4, 2017

    blocksize is hardcoded to 8192 in send() and _read_readable(), preventing
    efficient upload when using file-like body.

    Users of the module that are not interested in chunked encoding can rewrite
    the copy loop using HTTPConnection.send():

       conn = HTTPSConnection(...)
       while True:
           chunk =*1024)
           if not chunk:

    But fixing send() to use a configurable blocksize seems more useful.

    Also, users of requests do not have access the underlying connection, so
    they cannot use preferred buffer size.

    When reading from /dev/zero and uploading to server that drop the received
    data, larger buffer size gives 3X more throughput *and* 1/3 of cpu time.
    With real storage and network, the effect will probably be much smaller.

    @nirs nirs mannequin added 3.8 3.7 stdlib labels Nov 4, 2017
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    Mannequin Author

    @nirs nirs mannequin commented Nov 6, 2017

    When using highlevel request() api, users can control the block size by
    wrapping the file object with an iterator:

        class FileIter:
            def __init__(self, file, blocksize):
                self.file = file
                self.blocksize = blocksize
            def __iter__(self):
                while True:
                    datablock =
                    if not datablock:
                    yield datablock

    Adding configurable block size will avoid this workaround.

    @vstinner vstinner added type-feature and removed 3.8 labels Nov 6, 2017
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    @vstinner vstinner commented Nov 6, 2017

    New changeset ad455cd by Victor Stinner (Nir Soffer) in branch 'master':
    bpo-31945: Configurable blocksize in HTTP(S)Connection (bpo-4279)

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    @vstinner vstinner commented Nov 6, 2017

    Thank you Nir Soffer for this nice enhancement. Sadly, since it's a new feature, it cannot be backport to Python 3.6 nor 2.7, since it's a new feature.

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    @vstinner vstinner commented Nov 6, 2017

    The commit message contains much more information than the NEWS and What's New entries. Maybe the What's New entry can be completed, I don't know. In the meanwhile, I close the issue :-) Nir: Feel free to create a new PR if you want to complete the What's New entry ;-)

    @vstinner vstinner closed this as completed Nov 6, 2017
    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
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