Kyauta Mai Ɓoyewa & Bayyana Base64

Yadda Yake Aiki

Ɓoyewa da fassara Base64 a nan yana gudana gaba ɗaya a burauzarka ta amfani da abubuwan btoa/atob da aka gina na JavaScript da API na FileReader — babu uwar garke, babu lodawa, babu ɗakin karatu na waje. Don rubutu, wani mai lulluɓewa na encodeURIComponent/unescape yana tabbatar da haruffan Unicode suna ɓoyewa daidai; don fayiloli, FileReader.readAsDataURL() yana samar da bayanan Base64 kai tsaye.

1. 1
   Shigarwar rubutu: daidaita UTF-8

   Ana tura rubutu danye ta hanyar encodeURIComponent sannan unescape kafin a ba da shi ga btoa. Wannan mataki-biyu yana canja haruffan Unicode masu byte-da-yawa (emoji, haruffa masu lafazi, rubutun da ba na Latin ba) zuwa jerin byte da btoa zai iya ɓoyewa lafiya — tsallake wannan mataki zai jefar da kuskuren 'harafi a wajen zango' ga duk abin da yake wajen Latin-1.
2. 2
   Shigarwar fayil: FileReader API

   Lokacin da ka zaɓi fayil, hanyar FileReader.readAsDataURL() ta burauza tana karanta fayil ɗin a wurin nan kuma tana mayar da hanyar bayanai a tsarin data:<mime>;base64,<payload>. Kayan aikin yana cire prefix ɗin kuma yana ajiye bayanan Base64 danye kawai, yana goyon bayan kowane irin fayil har zuwa 20 MB.
3. 3
   Bambancin lafiya-na-URL (RFC 4648 §5)

   Sauya zuwa yanayin lafiya-na-URL yana amfani da maye gurbin haruffa uku ga fitarwar al'ada: + ya zama -, / ya zama _, kuma an cire = padding a ƙarshe. Wannan yayi daidai da haruffan RFC 4648 §5 da ake amfani da su a JWTs, ma'aunan URL, da sunayen fayil inda + da / za su bukaci percent-encoding.
4. 4
   Fassarawa: dawo da padding da atob

   A fassarawa, kayan aikin yana cire fararen sarari (yana sarrafa Base64 mai lulluɓewar MIME), yana mayar da haruffan lafiya-na-URL zuwa haruffan al'ada, sannan yana sake ƙara duk = padding da ya ɓace kafin ya kira atob. Ana mayar da bytes na fitarwa zuwa harafi na Unicode da decodeURIComponent(escape(...)) — madubin hanyar ɓoyewa.

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