New web interface

In addition to the console UIs, we also maintain a browser based (remote, via HTTP) interface to the tool, which provides an even more convenient way for code grokking. The main features of the web interface are:

  • Running and exploring semantic queries (both normal and context-sensitive queries)
  • Query construct assistant (auto-complete)
  • Persistent queries
  • Management of (possibly multiple) running queries
  • Database operations
  • Ability to mark files with error forms
  • Dependency examinations
  • Marking expressions as dynamic function references

Note that JavaScript must be enabled in the browser to be able to use this interface.



The web based UI is built upon the Yaws web server. To be able to start this interface you need a Yaws web server installed. Installation help:


To use the web interface, you have to provide the path to the YAWS' ebin directory when you compile the tool: bin/referl -build tool -yaws_path path_to_yaws_ebin

Starting up

We can start the server either with the referl script using the -web option, or from a running RefactorErl shell. Both cases provide a default configuration: server name localhost, port 8001, and address, which can be overridden.

Possible options:

  • yaws_path YPATH

The absolute location of your Yaws ebin directory.

  • yaws_listen YLISTEN

Valid IP address, which Yaws will listen to.

  • yaws_name YNAME

Valid domain name, which Yaws will be bound to.

  • yaws_port YPORT

Valid port number, which Yaws will be bound to.

  • browser_root BROOT

The web interface allows database operations. The root directory for those operations can be set with this parameter. (This option can be used multiple times if you wish to add more than one directories.)

  • restricted_mode ENABLED

A boolean value determining whether the web interface will be started in restricted mode. The default value is false.

Startup: referl script

You can pass any of the above options via command-line arguments (note that -web is mandatory). Example:

bin/referl -web
           -yaws_path /Users/V/yaws-1.95/ebin 
           -yaws_port 8000
           -yaws_name localhost
           -browser_root /Users/V/erlang
           -browser_root /Users/V/project
           -restricted_mode true

Startup: RefactorErl shell

We have two functions for starting the interface : ri:start_web/0 and ri:start_web/1. Without passing any parameters the web server starts up with the default configuration. The 1-arity function allows the interface to be configured using an Erlang proplist. Example:

    {yaws_name, localhost},
    {restricted_mode, true}]).

To specify multiple locations as root directories for database operations, you can pass a list of those locations with the browser_root property. Example:

    {browser_root, ["/Users/V/erlang", "/Users/V/project"]}]).

Shutting down

You are advised to always log out before shutting down the web server, because the log-out process deletes temporary, dynamically generated components of web pages. If the server has been started from the RefactorErl shell, then ri:stop_web() should be called in order to shut down the service.

Logging in & Restricted mode

In your browser, navigate to the server address defined by the configuration (the default is http://localhost:8001) after the web server has been successfully started. Services are allowed only to authorized people, so first you have to log in with a username. After a successful login the browser will be redirected to the queries page.

If the interface has been started by turning on restricted mode, standard users cannot access the Database and Errors pages and they cannot modify the content of the database. The administrator can still access these functionalities, but for that the password of the administrator account must be set first.

To set up or to reset the password you have to use a RefactorErl shell that directly runs on the server:

referl_ui_web2:set_web2_pass("admin", "*Password*").

After the password has been set the administrator can log in with the "admin" username and the set password, and he/she can access the restricted functionalities.

Global notifications

When someone starts/finishes a modification of the database (e.g. adding files), a notification will appear stating the modification has been started/finished. During any modification process most functionalities on the web interface will not be available. This restriction is global for the whole system. For further information, see: Configurable Jobserver

Stateful pages

The interface provides stateful pages. Due to stateful pages, one can share the actual state of a webpage displayed in his/her browser with a teammate by copying the URL from the address bar and sending it. Also you can easily navigate between previous states of the interface with your browser's back, forward and history functions.

Database operations

This service is available under the "Database" tab. The file browser panel is located at the left side of the page. You can either browse files which are located on the server ("Browse server"), or which had been loaded into the database ("Browse loaded files"). You can switch between these two options by clicking the button in the top right corner of the file browser box.

Browsing files on the server

The root directory of the browser is an optional configuration parameter. Possible values are:

  • When the browser_root parameter has been set during start up, the given value or values are the root element(s).
  • When the browser_root parameter has not been set during start up:
    • If the database had contained files before start up, the root elements are the directories of these files.
    • If the database had not contained files before start up, then RefactorErl’s lib directory will be the root.

In this mode, directories can be listed, the contents of files can be shown, and a selected directory or file can be added to the database. The selected directory or file is highlighted by a blue background. Database operations are indicated by a progress bar.

Searching is possible in both file system files, and loaded files.

Browsing loaded files

In this mode, directories' and files' contents can be listed, a selected file or directory can be reloaded to the database, dropped from the database, or can be pre-generated for the source code viewer. Status messages are displayed during the reloading/dropping/generating process, and also after the process has finished. The file browser displays the last directory that contains all the loaded files. Under the file browser box, there is a separate box for the function quicklist. In this box, the function definitions of the displayed file are listed if the file is added to the database. You can jump to the chosen function in the file by clicking on. If file is not displayed correctly, you can try to "repair" it by clicking the Refresh button in the upper right corner of the function quicklist window.

Dropping a file from the database does not imply removal from the file system.

Downloading files from the server

When browsing the database or file system contents on the "Queries" or "Database" pages you can right-click on the selected file and download it to your local machine by selecting "Download file" from the appearing context menu.

Running semantic queries

See Running semantic queries.

Free text search

On the queries page you can search for any text apart from running queries with the query input box.

The search button can be found in the dropdown menu which you can reach with the arrow next to the execute button. This is going to search in database and filesystem files too. The results will be displayed like a query result in group of files with occurrences. You can click any occurrence and the content with the result highlighted will be displayed.

WARNING: Searching in files with semicolon in its name will result in strange behaviour.


This service is available under the "Errors" tab.

If the database contains file(s) with error form(s), the list of errors will be displayed in a table. Each row in the table shows an error. Clicking the file name shows the file and highlights the position of the error.

If the database does not contain any files with error forms, a "No error" message is displayed.

Dependency examination

See Dependency examinations.

Code duplicates

See Code duplicates.

Logging out

You can log out by clicking the "Log out username" button. During the logout process the interface clears the users' session and redirects the browser to the login page. The interface does not delete the queries executed by the user, nor their results, and also keeps the state of the database.

Last modified 9 months ago Last modified on Oct 11, 2023, 3:00:46 PM