Upgrade to Pro — share decks privately, control downloads, hide ads and more …

Tumblr iOS architecture

Tumblr iOS architecture

Bryan Irace

August 06, 2014
Tweet

More Decks by Bryan Irace

Other Decks in Technology

Transcript

  1. iOS architecture
    Bryan Irace
    August 5, 2014

    View full-size slide

  2. Purpose of this talk
    • The iOS codebase should not be this magical, black
    box that you’re scared to look at or touch
    • All engineers should feel comfortable reading
    through the code (and opening pull requests)

    View full-size slide

  3. Relational DB
    File system
    Tumblr API Local storage
    Networking and storage
    Run loop (waits for user interaction)

    View full-size slide

  4. Sync engine
    UI Sync
    engine
    User requested posts
    User created a post,
    liked/followed something,
    etc.
    New posts persisted
    No Internet? No problem
    Local storage
    Outgoing posts are queued,
    retried when connected
    Fetch new posts if connected,
    no worries if not

    View full-size slide

  5. Core Data
    Basically an ORM, but don’t call it that

    View full-size slide

  6. Our database is (mostly)
    just a cache
    Provides speed plus a nice offline experience without
    complication

    View full-size slide

  7. Controller
    Controller
    View
    View
    MVC
    Controller View
    View View
    View
    What you see on screen and
    interact with
    Exists in a
    hierarchy
    Drawn programatically or
    using a visual editor
    (Interface Builder)
    Manages a screenful
    (or so) of information
    Responds to user
    interaction
    Contains only
    presentation
    logic
    Has a single
    view
    Populates its
    view with data

    View full-size slide

  8. Adaptive layout
    • iOS 1-7
    • Check if we’re running on an iPhone or iPad
    • Check if we’re in portrait or landscape
    • iOS 8
    • At any point, app will be either vertically/horizontally
    “regular” or “compact”
    • This can change based on rotation, other factors

    View full-size slide

  9. Post rendering
    ryan:

    The site may
    crash. 16-
    bitch met href="http://tmblr.co/
    mJmaPYlIVDe7tP9jhKEHlRw">
    david.

    Tumblr - making dreams
    come true (for David)
    API response
    XML parser
    Mapping of
    character ranges
    to semantic
    section types (and
    attributes)
    Output string +
    data structure
    Or “Why inline embeds and stuff don’t show up”

    View full-size slide


  10. ryan.tumblr.com/post/
    93783287034/the-site-may-
    crash-16-bitch-met-
    david">ryan:


    The site may crash. href="http://tmblr.co/
    mqneDxY-
    aNcK8DhWHP23qvw">16-bitch
    a> met tmblr.co/
    mJmaPYlIVDe7tP9jhKEHlRw">da
    vid.



    Tumblr - making dreams
    come true (for David)

    (0, 4): [
    {
    type: 'link',
    attributes: {
    url: ‘http://ryan.tumblr.com/post/…’
    }
    }
    ],
    (0, 6): [
    { type: 'paragraph' }
    ],
    (46, 45): [
    { type: 'paragraph' }
    ],
    (6, 40): [
    { type: 'blockquote' },
    { type: 'paragraph' }
    ],
    (26, 8): [
    {
    type: 'link',
    attributes: { url: ‘http://tmblr.co/…’ }
    }
    ],
    (39, 5): [
    {
    type: 'link',
    attributes: { url: ‘http://tmblr.co/…’ }
    }
    ]
    ryan:\nThe site may crash. 16-bitch met david.\nTumblr - making dreams come true (for David)

    View full-size slide

  11. TextKit
    NSMutableAttributedString *string = [[NSMutableAttributedString alloc] initWithString:
    @"ryan:\nThe site may crash. 16-bitch met david.\nTumblr - making dreams
    come true (for David)"];
    !
    // Loop through ranges, add the right attributes to each range
    !
    [postContent addAttributes:@{
    NSLinkAttributeName : [NSURL URLWithString:@“http://ryan.tumblr.com/post/…”]
    } range:NSMakeRange(0, 4)];
    !
    // Lots of work required to support things like nested blockquote indentation, nested
    lists, inline images, etc.

    View full-size slide

  12. Yes, I realize we’re kind of
    implementing a web
    browser here
    All in the name of performance

    View full-size slide

  13. GIFs
    • Save each individual frame as a JPEG (plus a
    metadata file)
    • Play by looping through the individual frames
    • Don’t read them all into memory at once

    View full-size slide

  14. • Think Gems/Bundler, NPM, etc.
    • Used for both internal and third-party
    dependencies
    • Downloads as well as integrates with Xcode
    project file, compilation settings, etc.

    View full-size slide

  15. Internal libraries
    BRYMailToURIParser*

    BRYParseKeyboardNotification*

    SnoopySDK

    TMCache*

    TMTumblrSDK*

    TMVideoPlayer

    TumblrCommon
    * Open source

    View full-size slide

  16. Third-party libraries
    CHTCollectionViewWaterfallLayout

    GRMustache

    HockeySDK

    JCKeyPathValidator

    JRSwizzle

    MTMigration

    PocketAPI

    ObjectiveCHTMLParser

    Reachability

    View full-size slide

  17. Application lifecycle
    • Apps can be purged from memory at any time, if iOS
    needs to reclaim memory
    • iOS 7 added “background fetch” – app can
    periodically update itself even if it had previously
    been killed
    • Apps can perform “background tasks” (within reason)
    • e.g. User creates a post and then backgrounds
    the app – post will continue uploading

    View full-size slide

  18. Push notifications
    Notification
    App is foregrounded
    App is backgrounded
    App is
    foregrounded
    and given
    payload
    App is given
    payload
    immediately
    iOS displays notification
    without app’s involvement

    View full-size slide

  19. Inter-app communication
    • Apps define protocols that they can handle, e.g. “tumblr://“
    • We’ve support a number of URLs, including:
    • tumblr://x-callback-url/tag?tag=gif
    • tumblr://x-callback-url/blog?blogName=bryan
    • tumblr://x-callback-url/quote?
    quote=Quote&source=Source
    • x-callback-url is an unofficial specification for how iOS URLs should
    be structured
    • x-success and x-error URL parameters are used to return
    the user to the app where they came from

    View full-size slide

  20. Inter-app communication
    Apps can also register to open files of a
    certain type, e.g. JPEG or MP4

    View full-size slide

  21. Inter-app communication
    iOS 8 allows apps to expose “share
    extensions”

    View full-size slide