Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
How to Use In-Memory Streams
Search
HayaoSuzuki
August 29, 2020
Technology
1
5.2k
How to Use In-Memory Streams
PyCon JP 2020
HayaoSuzuki
August 29, 2020
Tweet
Share
More Decks by HayaoSuzuki
See All by HayaoSuzuki
Tasting "Python Distilled"
hayaosuzuki
0
290
Let's implement useless Python objects
hayaosuzuki
0
1.9k
How to Write Robust Python Code
hayaosuzuki
5
4.3k
Unknown Evolution of the Built-in Function pow
hayaosuzuki
0
1.4k
Python for Everyday
hayaosuzuki
1
2.1k
Do you know cmath module?
hayaosuzuki
0
3.2k
Elementary Number Theory with Python
hayaosuzuki
1
3.5k
Django QuerySet "ARE" Patterns
hayaosuzuki
0
3.3k
A Modernization of Legacy Django Based Applications
hayaosuzuki
1
7.8k
Other Decks in Technology
See All in Technology
LangChain Interrupt & LangChain Ambassadors meetingレポート
os1ma
2
310
敢えて生成AIを使わないマネジメント業務
kzkmaeda
2
450
ネットワーク保護はどう変わるのか?re:Inforce 2025最新アップデート解説
tokushun
0
210
開発生産性を測る前にやるべきこと - 組織改善の実践 / Before Measuring Dev Productivity
kaonavi
10
4.6k
Claude Code に プロジェクト管理やらせたみた
unson
6
4.1k
生成AI開発案件におけるClineの業務活用事例とTips
shinya337
0
260
開発生産性を組織全体の「生産性」へ! 部門間連携の壁を越える実践的ステップ
sudo5in5k
2
7.2k
american aa airlines®️ USA Contact Numbers: Complete 2025 Support Guide
aaguide
0
150
MobileActOsaka_250704.pdf
akaitadaaki
0
130
How Do I Contact HP Printer Support? [Full 2025 Guide for U.S. Businesses]
harrry1211
0
120
無意味な開発生産性の議論から抜け出すための予兆検知とお金とAI
i35_267
4
13k
Lazy application authentication with Tailscale
bluehatbrit
0
210
Featured
See All Featured
Speed Design
sergeychernyshev
32
1k
Navigating Team Friction
lara
187
15k
Distributed Sagas: A Protocol for Coordinating Microservices
caitiem20
331
22k
Why Our Code Smells
bkeepers
PRO
336
57k
Docker and Python
trallard
44
3.5k
10 Git Anti Patterns You Should be Aware of
lemiorhan
PRO
656
60k
Building a Modern Day E-commerce SEO Strategy
aleyda
42
7.4k
Building Flexible Design Systems
yeseniaperezcruz
328
39k
Typedesign – Prime Four
hannesfritz
42
2.7k
The MySQL Ecosystem @ GitHub 2015
samlambert
251
13k
RailsConf 2023
tenderlove
30
1.1k
Faster Mobile Websites
deanohume
307
31k
Transcript
ΠϯϝϞϦʔετϦʔϜ׆༻ज़ How to Use In-Memory Streams Hayao Suzuki PyCon JP
2020 August 29, 2020
ൃදʹࡍͯ͠ GitHub ʹࢿྉ͕͋Γ·͢ › https://github.com/HayaoSuzuki/pyconjp2020 Twitter ͷϋογϡλά › #pyconjp_1 PyCon
JP Fellow Slack › #jp-2020-track-1 2 / 27
Who am I ? ͓લ୭Α Name Hayao Suzukiʢླɹॣʣ Twitter @CardinalXaro
Work Python Programmer at iRidge, Inc. 3 / 27
Who am I ? Technical Reviewer › Effective Python ୈ
2 ൛ (O’Reilly Japan) › ಈֶ͔ͯ͠Ϳྔࢠίϯϐϡʔλϓϩάϥϛϯά (O’Reilly Japan) https://xaro.hatenablog.jp/ ʹϦετ͕͋Γ·͢ɻ 4 / 27
Who am I ? Selected Talks › ϨΨγʔ Django ΞϓϦέʔγϣϯͷݱԽ
(DjangoCongress JP 2018) › SymPy ʹΑΔࣜॲཧ (PyCon JP 2018) › Python ͱָ͠Ήॳ (PyCon mini Hiroshima 2019) › ܅ cmath Λ͍ͬͯΔ͔ (PyCon mini Shizuoka 2020) https://xaro.hatenablog.jp/ ʹϦετ͕͋Γ·͢ɻ 5 / 27
ࠓͷඪ ͜Μͳ՝Λղܾ͍ͨ͠ʂ › Πϯλʔωοτܦ༝Ͱ GB αΠζͷσʔλΛऔಘ͠ɺCSV ϑΝΠϧʹՃ͢Δ › Ϋϥυ্ʹߏஙͨ͠طଘͷγεςϜʹՃ͢ΔܗͰ࣮͢Δ ›
ຖ࣮ߦ͢Δ ΫϥυαʔϏεैྔ՝ۚ ͳΔ͘ਝʹॲཧ͍ͨ͠ʂ 6 / 27
ࠓͷඪ ॲཧͷྲྀΕ › Πϯλʔωοτܦ༝Ͱ GB αΠζͷσʔλΛऔಘ͢Δ › GB αΠζͷσʔλΛ
CSV ϑΝΠϧʹՃ͢Δ › CSV ϑΝΠϧΛ ZIP ѹॖ͢Δ › ZIP ѹॖσʔλΛΫϥυετϨʔδʹΞοϓϩʔυ͢Δ ੳ › σʔλαΠζ͕େ͖͍ › σʔλͷՃ୯७ͳॲཧ 7 / 27
ࠓͷඪ ϘτϧωοΫͲ͔͜ › ZIP ѹॖͦΕ΄ͲେมͰͳ͍ › σʔλՃ୯७ͳॲཧ › ϘτϧωοΫ I/O
ॲཧʹ͋Γͦ͏ Կͱ͔ͯ͠ I/O ॲཧΛਝʹॲཧ͍ͨ͠ʂʂʂ 8 / 27
Today’s Theme In-Memory Streams 9 / 27
Stream? ͦͦετϦʔϜͬͯԿʁ ετϦʔϜϑΝΠϧΦϒδΣΫτͰ͋Δɻ 10 / 27
File Object? ϑΝΠϧΦϒδΣΫτͬͯԿʁ › read() write() ͳͲͷϝιουΛ࣋ͭΦϒδΣΫτ › σΟεΫ্ͷϑΝΠϧผͷॴʹ͋ΔετϨʔδɺೖग़ྗػثͱ
ΓͱΓ͕Ͱ͖Δ 11 / 27
File Object? ϑΝΠϧΦϒδΣΫτͨͪ › ੜόΠφϦϑΝΠϧ › όοϑΝ͖όΠφϦϑΝΠϧ › ςΩετϑΝΠϧ 12
/ 27
͍ํ ςΩετϑΝΠϧ f = open("myfile.txt", "r") όοϑΝ͖όΠφϦ f = open("myfile.jpg",
"rb") 13 / 27
open ؔͷཪଆ open ԿΛ͍ͯ͠Δͷ͔ʁ OS ͷγεςϜίʔϧ API ΛݺͿ 14 /
27
open ؔͷཪଆ ྫɿCSV ʹՃ͢Δ with open("events.csv", "w") as csv_file: fieldnames
= ["title", "started_at", "ended_at"] writer = csv.DictWriter(csv_file, fieldnames) writer.writeheader() writer.writerows(events) 15 / 27
open ؔͷཪଆ ྫɿWindows › CreateFileʢϑΝΠϧͷΞΫηεݖऔಘʣ › QueryAllInformationFileʢϑΝΠϧใͷऔಘʣ › WriteFileʢϑΝΠϧॻ͖ࠐΉʣ ›
CloseFileʢϑΝΠϧΛด͡Δʣ Process Monitor ܦ༝Ͱ֬ೝͨ͠ɻ 16 / 27
open ؔͷཪଆ ྫɿUbuntu on WSL › openat ʢϑΝΠϧͷΦʔϓϯʣ › fstatʢϑΝΠϧใͷऔಘʣ
› ioctlʢσόΠε੍ޚʣ › lseekʢϑΝΠϧͷγʔΫʣ › writeʢϑΝΠϧॻ͖ࠐΉʣ › closeʢϑΝΠϧΛด͡Δʣ strace ܦ༝Ͱ֬ೝͨ͠ɻ 17 / 27
࠷ޙʹস͏ͷ୭ͩ ࠷ऴతͳՌͲ͜ʹஔ͘ʁ › ϑΝΠϧΛϩʔΧϧʹอଘ͢Δͷ͕ΰʔϧͰͳ͍ › ϑΝΠϧΛ AWS S3 ͳͲͷ֎෦ʹஔ͖͍ͨ ϩʔΧϧσόΠεʹϑΝΠϧΛॻ͖ࠐΈͨ͘ͳ͍ʂ
18 / 27
Today’s Theme In-Memory Streams 19 / 27
ΠϯϝϞϦʔετϦʔϜ ΠϯϝϞϦʔετϦʔϜͱ › str bytes ΛϑΝΠϧΦϒδΣΫτͷΑ͏ʹѻ͑Δ › ಡΈॻ͖ՄೳɺϥϯμϜΞΫηεՄೳ 20
/ 27
StringIO StringIO ςΩετϑΝΠϧͷͨΊͷΠϯϝϞϦετϦʔϜ ྫɿCSV Λ StringIO ͰऔΓѻ͏ import io with
io.StringIO() as csv_file: fieldnames = ["title", "started_at", "ended_at"] writer = csv.DictWriter(csv_file, fieldnames) writer.writeheader() writer.writerows(events) 21 / 27
BytesIO BytesIO όοϑΝ͖όΠφϦϑΝΠϧͷͨΊͷΠϯϝϞϦετϦʔϜ ྫɿPNG Λ BytesIO ͰऔΓѻ͏ import io with
io.BytesIO(png_bytes) as f: png_header = f.read(8) print(png_header) # b'\x89PNG\r\n\x1a\n' 22 / 27
෮शɿࠓͷඪ ॲཧͷྲྀΕ › Πϯλʔωοτܦ༝Ͱ GB αΠζͷσʔλΛऔಘ͢Δ › GB αΠζͷσʔλΛ
CSV ϑΝΠϧʹՃ͢Δ › CSV ϑΝΠϧΛ ZIP ѹॖ͢Δ › ZIP ѹॖσʔλΛΫϥυετϨʔδʹΞοϓϩʔυ͢Δ 23 / 27
σʔλΛΠϯλʔωοτܦ༝Ͱऔಘ͢Δ ྫɿConnpass API Λίʔϧ͢Δ with urllib.request.urlopen(url) as response: events =
json.load(response)["events"] 24 / 27
σʔλΛՃ͢Δ ྫɿAPI ͷऔಘ݁ՌΛ CSV ʹ͢Δ with io.StringIO() as ts: header
= ["title", "started_at", "ended_at"] writer = csv.DictWriter(ts, fieldnames=header) writer.writeheader() writer.writerows(events) 25 / 27
σʔλΛѹॖ&Ξοϓϩʔυ ྫɿZIP ʹѹॖͯ͠ AWS S3 ʹΞοϓϩʔυ with io.BytesIO() as bs:
with zipfile.ZipFile(bytes_stream, "w") as zf: zf.writestr("events.csv", ts.getvalue()) bs.seek(0) # ϑΝΠϧγʔΫ͕ϙΠϯτ s3.upload_fileobj(bs, "bucket", "events.zip") 26 / 27
Conclusion ·ͱΊ › io ϞδϡʔϧʹΠϯϝϞϦʔετϦʔϜؚ͕·ΕΔɻ › str bytes ΛϑΝΠϧΦϒδΣΫτͷΑ͏ʹѻ͏͜ͱ͕Ͱ͖Δɻ
› ௨ৗͷ open ͱҟͳΓγεςϜίʔϧ͕ݺΕͳ͍ɻ › σΟεΫͷ I/O ΛݮΒ͍ͨ͠ɺ·ͨͰ͖ͳ͍ঢ়گԼͰͷར༻ ͕࠷దͰ͋Δɻ io ϞδϡʔϧΛօ༷ͷಓ۩ശʹೖΕ͍ͯͩ͘͞ʂ 27 / 27