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
5.1k
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
1.8k
How to Write Robust Python Code
hayaosuzuki
5
4.2k
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
OpenTelemetry Collector internals
ymotongpoo
3
200
MCPを利用して自然言語で3Dプリントしてみよう!
hamadakoji
0
1.2k
おれのAI活用の現状とこれから
tsukasagr
0
120
Drawing with LLMs
rist
0
230
Digitization部 紹介資料
sansan33
PRO
1
4k
Javaアプリケーションの配布とパッケージング / Distribution and packaging of Java applications
hogelog
2
530
Two-Tower モデルで実現する 検索リランキング / Shibuya_AI_2
visional_engineering_and_design
2
130
医療業界に特化した音声認識モデル構築のためのアノテーションの実態
thickstem
0
510
入門 ESlint Typegen #TSKaigi #TSKaigi2025_kataritai
bengo4com
0
2k
Data Hubグループ 紹介資料
sansan33
PRO
0
1.8k
Oracle Cloud Infrastructureデータベース・クラウド:各バージョンのサポート期間
oracle4engineer
PRO
48
33k
研究開発部メンバーの働き⽅ / Sansan R&D Profile
sansan33
PRO
3
17k
Featured
See All Featured
Code Reviewing Like a Champion
maltzj
524
40k
Reflections from 52 weeks, 52 projects
jeffersonlam
349
20k
Adopting Sorbet at Scale
ufuk
77
9.4k
The Web Performance Landscape in 2024 [PerfNow 2024]
tammyeverts
7
640
Stop Working from a Prison Cell
hatefulcrawdad
269
20k
GraphQLの誤解/rethinking-graphql
sonatard
71
11k
Designing Experiences People Love
moore
142
24k
Optimising Largest Contentful Paint
csswizardry
37
3.3k
Building Adaptive Systems
keathley
42
2.6k
The Power of CSS Pseudo Elements
geoffreycrofte
76
5.8k
Learning to Love Humans: Emotional Interface Design
aarron
273
40k
Refactoring Trust on Your Teams (GOTO; Chicago 2020)
rmw
34
3k
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