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HTML Pages

abapGitAbout 5 minui

This documentation covers page creation, HTML rendering, and event handling.

TL;DR

  • To create a new page in abapGit you subclass ZCL_ABAPGIT_GUI_PAGE and redefine RENDER_CONTENT method (also consider separating components that implement ZIF_ABAPGIT_GUI_RENDERABLE directly, this will probably become the primary approach in future)
  • Use ZCL_ABAPGIT_HTML to collect HTML content - method add accepts strings, string_tables, and instances of ZCL_ABAPGIT_HTML
  • Use ZCL_ABAPGIT_HTML=>ICON to render icons
  • Use ZCL_ABAPGIT_HTML=>A to render anchors, don't render them manually <a>...</a>
  • Please, please, care about usability, content readability, and style in general 🙏 😉
  • Check ZCL_ABAPGIT_GUI_CHUNK_LIB for some existing HTML chunks like render_error
  • To register postponed HTML parts, scripts, and hotkeys - access corresponding methods via gui_services method of zcl_abapgit_gui_component

GUI Components

abapGit UI is based on HTML and CL_GUI_HTML_VIEWER. The main parts are:

  • ZCL_ABAPGIT_GUI - the class which initializes CL_GUI_HTML_VIEWER and manages page stack
  • ZCL_ABAPGIT_GUI_ASSET_MANAGER - manages static assets like images, CSS, JS code, and fonts
  • ZCL_ABAPGIT_HTML - helper for HTML accumulation and rendering
  • ZCL_ABAPGIT_GUI_ROUTER - abapGit specific global event handling, main to route between the pages or run globally defined actions like repo installation
  • ZCL_ABAPGIT_GUI_PAGE - base class for pages. It renders typical HTML headers and abapGit-related java scripts. ~So in most cases you probably just want to subclass it and render just the content~
  • ZCL_ABAPGIT_GUI_COMPONENT - base class for GUI components. Gives access to gui_services to register postponed HTML parts, scripts, and hotkeys. Usually, it is a good idea to subclass from it, if you want to use these features.
  • ZIF_ABAPGIT_GUI_RENDERABLE - interface which a renderable component must expose to be able to interact with ZCL_ABAPGIT_GUI
  • ZIF_ABAPGIT_GUI_EVENT_HANDLER - interface which a component must expose to be able to register itself as an event handler in ZCL_ABAPGIT_GUI
  • ZIF_ABAPGIT_GUI_HOTKEYS - interface which a component must expose to be able to register hotkey actions

Rendering Content

An example of RENDER_CONTENT (or any other helper method with HTML output)

METHOD render_content.

    CREATE OBJECT ro_html.

    ro_html->add( '<div>' ).
    ro_html->add( '<h1>My content</h1>' ).
    ro_html->add_icon( 'star/error' ).
    ro_html->add_a(
        iv_txt = 'click me'
        iv_act = 'some_event_handled_in_abap' ).
    ro_html->add( render_some_complex_stuff( ) ).
    ro_html->add( '</div>' ).

ENDMETHOD.

HTML Helper

ro_html which is the instance of ZCL_ABAPGIT_HTML is a helper tool for HTML rendering. It accumulates HTML content and then can output it with render method. It has a couple of important methods:

  • ADD - adds a chunk to accumulated HTML. You can pass a string or another ZCL_ABAPGIT_HTML instance. In the example above render_some_stuff may either return a string or have the same pattern as render_content (retuning ZCL_ABAPGIT_HTML instance)
  • ADD_ICON and ICON - renders an icon. abapGit uses web fonts to render icons (see adding icons). The method accepts the icon name and a CSS class name which represents a color separated by '/'. E.g., in the example above it will render 'star' icon and assign 'error' CSS class to it which has red color in the abapGit styles. The method has its static brother ZCL_ABAPGIT_HTML=>ICON which is more convenient in some cases and just returns a rendered HTML string.
  • ADD_A and A - render a link (anchor) (A - static method). It is strongly suggested that you use this method instead of rendering <a> tags directly. Params:
    • IV_TXT - text to be rendered inside the anchor
    • IV_TYP - the type of action done on click. 3 options:
      • zif_abapgit_html=>c_action_type-url- direct link to an URL,
      • ...-sapevent (the default) - pass an event to sap handler,
      • ...-onclick - call a JS function,
      • ...-dummy - just render an anchor but no action
    • IV_ACT - depending on the type should be either URL or sapevent name or JS function to call
    • IV_OPT - zif_abapgit_html=>c_html_opt-strong or ...-cancel or ...-crossout - some semantic predefined styles to add to the link
    • IV_CLASS - additional CSS class, if needed
    • IV_STYLE - additional direct styles to use (generally discouraged, please use CSS classes instead)
    • IV_ID - id of the anchor (may be needed for JS code)
  • SET_TITLE - the method is used for debugging purposes for postponed HTML parts. As it is not visible which class registered an HTML part, the title can be used to specify the origin.

Renderables

Sub-classing ZCL_ABAPGIT_GUI_PAGE is not the only way to render the content. You may want to separate some visual component that is not a page e.g. ZCL_ABAPGIT_GUI_VIEW_REPO is a class like that. In essence, you have to implement ZIF_ABAPGIT_GUI_RENDERABLE and its method - render. Then you can reuse it or even pass it directly to the GUI class as a page to render.

It makes sense to also subclass your component from ZCL_ABAPGIT_GUI_COMPONENT. This class has a protected gui_services method returning the singleton instance of ZIF_ABAPGIT_GUI_SERVICES. The GUI services are good for:

  • registering self as an event handler (register_event_handler). Importantly, later registered event handlers have higher priority (processing is done from bottom to top)
  • accessing hotkey services (get_hotkeys_ctl) - to register own hotkeys for the page (hotkeys are combined from the whole component stack)
  • registering postponed HTML parts (get_html_parts)

Postponed HTML Parts

Components may have postponed parts, e.g. scripts or hidden forms. These chunks may need to be rendered in another location on the page (e.g. scripts are rendered at the end). There is a mechanism to enable it:

    " ... somewhere within render
    gui_services( )->get_html_parts( )->add_part(
      iv_collection = c_html_parts-scripts
      ii_part       = render_my_scripts( ) ).

where render_my_scripts( ) must return an instance of ZCL_ABAPGIT_HTML.

Currently, two collections are supported out of the box - scripts and hidden_forms (see definition of zcl_abapgit_gui_component). Scripts rendered after the page body. Hidden forms right before the end of the body. But this does not limit you to these categories only - you may register your own collections to exchange postponed parts between components supported by you. The collection is just a named list of ZCL_ABAPGIT_HTML instances.

Router and Event Handlers

To process sapevents in abap the component (page) must implement ZIF_ABAPGIT_GUI_EVENT_HANDLER=>on_event. It imports ii_event instance which represents sapevent handler of cl_gui_html_viewer. In particular:

  • ii_event->mv_action - sapevent code (part of URL before ?)
  • ii_event->mv_getdata - raw URL query (part of URL after ?)
  • ii_event->mt_postdata - raw post data (if present)
  • ii_event->mi_gui_services - the instance of GUI services for easier access
  • ii_event->query() - returns parsed url query (k1=v1&k2=v2...) in form of string_map. Param names are uppercased (by default). Params that are not uniform are not parsed (k1=v1&k2 - will result in k1 only). Params can be addressed in 2 typical ways:
    • ii_event->query( )->get( 'XXX' )
    • or ii_event->query( )->to_abap( changing cs_container = ls_struc_with_fields )
    • query string_map is immutable (attempt to set will raise an exception)
    • accepts optional iv_upper_cased param to unify param names (default = true)
  • ii_event->form_data() - attempts to parse post_data assuming it is set of key value pairs. Returns a string map. Otherwise behaves as query() above. iv_upper_cased = false by default.

Events can be processed on 2 levels - in page/component or in the router. On new event:

  • the GUI goes through the event handlers stack - a list of components that registered themselves as event handlers during rendering via gui_services
  • the processing is done from the last registered handler to the first one (stack top to bottom)
  • the first event handler that returns "handled" status breaks the cycle (see below how this is indicated)
  • if the event was not handled by the handlers in the stack the event would be passed to the router

Router (ZCL_ABAPGIT_GUI_ROUTER) is the class that handles global abapGit commands like opening specific pages and actions like repo installation/deletion.

In order to indicate the result of event handling an on_event implementation must return rs_handled-state (element of zcl_abapgit_gui=>c_event_state) and, optionally, rs_handled-page:

  • not_handled (same as initial) - the event was not handled, process it by the next handler (e.g. the router)
  • re_render - just re-render the current page (probably an internal state of the page object was changed so the visualization should too)
  • new_page - render ei_page
  • go_back - render the previous page in the call stack (e.g. user pressed F3)no_more_act - the action was handled, no further processing required, and in particular no re-rendering
  • new_page_w_bookmark - ei_page and put a bookmark - allows using go_back_to_bookmark action that will skip all the page stack till the first bookmark
  • new_page_replacing - ei_page and replace the current page in stack (so that F3 returns to the parent of the current page)
  • go_back_to_bookmark - go back and skip all the page stack till the first bookmark (works with new_page_w_bookmark)

Hotkey

In a nutshell:

  " somewhere within render
  gui_services( )->get_hotkeys_ctl( )->register_hotkeys( me ).

The component must implement zif_abapgit_gui_hotkeys and return the list of keys, their human-readable meaning, and the corresponding event to invoke.

  METHOD zif_abapgit_gui_hotkeys~get_hotkey_actions.

    DATA ls_hotkey_action LIKE LINE OF rt_hotkey_actions.

    ls_hotkey_action-ui_component = 'Stage'. " <<< This is to define origin of hotkeys

    ls_hotkey_action-description  = |Patch|. " <<< Human readable description
    ls_hotkey_action-action       = zif_abapgit_definitions=>c_action-go_patch. " <<< abapgit-wide action to open patch page
    ls_hotkey_action-hotkey       = |p|.     " <<< Key
    INSERT ls_hotkey_action INTO TABLE rt_hotkey_actions.

    ls_hotkey_action-description  = |Diff|.
    ls_hotkey_action-action       = zif_abapgit_definitions=>c_action-go_diff.
    ls_hotkey_action-hotkey       = |d|.
    INSERT ls_hotkey_action INTO TABLE rt_hotkey_actions.

  ENDMETHOD.