PNG Image Generator Skeleton Application

Web application skeleton using Fano, Pascal web application framework. This web application generates PNG image on the fly. The image resolution is defined by user in Url. For example

http://[your app hostname]/image/{width}x{height}.png

Where {width} and {height} is integer value between 10 to 300. See live example.

Requirement

• Free Pascal >= 3.0
• Fano CLI
• Apache mod_cgi or Apache mod_cgid
• Apache mod_rewrite
• Administrative privilege to setup virtual host

Installation

TLDR

Make sure that your system have met above requirements.

$ git clone https://github.com/fanoframework/fano-app-img.git --recursive
$ cd fano-app-img
$ ./tools/config.setup.sh
$ ./build.sh
$ sudo fanocli --deploy-cgi=img.fano

Fano CLI is used to setup virtual host. If you prefer setup virtual host manually, you can skip last command.

Open internet browser and open http://img.fano, you should see application like live example.

Build

Free Pascal installation

Make sure Free Pascal is installed. Run

$ fpc -i

If you see something like Free Pascal Compiler version 3.0.4, you are good to go.

Clone this repository

$ git clone https://github.com/fanoframework/fano-app-img.git --recursive

--recursive is needed so git also pull Fano repository.

If you are missing --recursive when you clone, you may find that fano directory is empty. In this case run

$ git submodule update --init

To update Fano to its latest commit, run

$ git checkout master && git submodule foreach --recursive git pull origin master

Above command will checkout to master branch of this repository and pull latest update from master branch of Fano repository.

Copy *.cfg.sample to *.cfg. Make adjustment as you need in build.cfg, build.prod.cfg, build.dev.cfg and run build.sh shell script (if you are on Windows, then build.cmd).

These *.cfg files contain some Free Pascal compiler switches that you can turn on/off to change how executable is compiled and generated. For complete explanation on available compiler switches, consult Free Pascal documentation.

$ cp app/config/config.json.sample app/config/config.json
$ cp build.prod.cfg.sample build.prod.cfg
$ cp build.dev.cfg.sample build.dev.cfg
$ cp build.cfg.sample build.cfg
$ ./build.sh

tools/config.setup.sh shell script is provided to simplify copying those configuration files. Following shell command is similar to command above.

$ ./tools/config.setup.sh
$ ./build.sh

By default, it will output binary executable in public directory.

Build for different environment

To build for different environment, set BUILD_TYPE environment variable.

Build for production environment

$ BUILD_TYPE=prod ./build.sh

Build process will use compiler configuration defined in fano/fano.cfg, build.cfg and build.prod.cfg. By default, build.prod.cfg contains some compiler switches that will aggressively optimize executable both in speed and size.

Build for development environment

$ BUILD_TYPE=dev ./build.sh

Build process will use compiler configuration defined in fano/fano.cfg, build.cfg and build.dev.cfg.

If BUILD_TYPE environment variable is not set, production environment will be assumed.

Change executable output directory

Compilation will output executable to directory defined in EXEC_OUTPUT_DIR environment variable. By default is public directory.

$ EXEC_OUTPUT_DIR=/path/to/public/dir ./build.sh

Change executable name

Compilation will use executable filename as defined in EXEC_OUTPUT_NAME environment variable. By default is app.cgi filename.

$ EXEC_OUTPUT_NAME=index.cgi ./build.sh

Run

Run with a webserver

Setup a virtual host. Please consult documentation of web server you use. You can skip this section if you use Fano CLI to setup virtual host for you.

For example on Apache,

<VirtualHost *:80>
     ServerName www.example.com
     DocumentRoot /home/example/app/public

     <Directory "/home/example/app/public">
         Options +ExecCGI
         AllowOverride FileInfo
         Require all granted
         DirectoryIndex app.cgi
         AddHandler cgi-script .cgi
     </Directory>
</VirtualHost>

On Apache, you will need to enable CGI module, such as mod_cgi or mod_cgid. If CGI module not loaded, above virtual host will cause app.cgi is downloaded instead of executed.

For example, on Debian, this will enable mod_cgi module.

$ sudo a2enmod cgi
$ sudo systemctl restart apache2

Depending on your server setup, for example, if you use .htaccess, add following code:

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^(.*)$ app.cgi [L]
</IfModule>

and put .htaccess file in same directory as app.cgi file (i.e., in app/public directory).

Content of .htaccess basically tells Apache to serve existing files/directories directly. For any non-existing files/directories, pass them to our application.

If successful, when you visit application URL, for example

http://[your_app_name]/image/100x100.png
http://[your_app_name]/image/200x200.png

You will get PNG image displayed.

Simulate run on command line

$ cd app/public
$ REQUEST_METHOD=GET \
  REQUEST_URI=/test/test \
  SERVER_NAME=juhara.com \
  ./app.cgi

tools/simulate.run.sh is bash script that can be used to simplify simulating run application in shell.

$ ./tools/simulate.run.sh

or to change route to access, set REQUEST_URI variable.

$ REQUEST_URI=/test/test ./simulate.run.sh

This is similar to simulating browser requesting this page,for example,

$ wget -O- http://[your fano app hostname]/test/test

However, running using tools/simulate.run.sh allows you to view output of heaptrc unit for detecting memory leak (if you enable -gh switch in build.dev.cfg).

Deployment

You need to deploy only executable binary. Any pas or inc files or shell scripts is not needed in deployment machine in order application to run.

Known Issues

Issue with GNU Linker

When running build.sh script, you may encounter following warning:

/usr/bin/ld: warning: app/public/link.res contains output sections; did you forget -T?

This is known issue between Free Pascal and GNU Linker. See FAQ: link.res syntax error, or "did you forget -T?"

However, this warning is minor and can be ignored. It does not affect output executable.

Issue with unsynchronized compiled unit with unit source

Sometime Free Pascal can not compile your code because, for example, you deleted a unit source code (.pas) but old generated unit (.ppu, .o, .a files) still there or when you switch between git branches. Solution is to remove those files.

By default, generated compiled units are in bin/unit directory. But do not delete README.md file inside this directory, as it is not being ignored by git.

$ rm bin/unit/*.ppu
$ rm bin/unit/*.o
$ rm bin/unit/*.rsj
$ rm bin/unit/*.a

Following shell command will remove all files inside bin/unit directory except README.md file.

$ find bin/unit ! -name 'README.md' -type f -exec rm -f {} +

tools/clean.sh script is provided to simplify this task.

Windows user

Free Pascal supports Windows as target operating system, however, this repository is not yet tested on Windows. To target Windows, in build.cfg replace compiler switch -Tlinux with -Twin64 and uncomment line #-WC to become -WC.

Lazarus user

While you can use Lazarus IDE, it is not mandatory tool. Any text editor for code editing (Atom, Visual Studio Code, Sublime, Vim etc) should suffice.