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Stock ticker example:

• creates a new ticker (stock name and its price) or updates an existing one,
  
  
• displays the stock ticker database.
  

In a nutshell: MariaDB; command line; web browser; Nginx; Unix sockets; 3 source files, 55 lines of code.
Stock value is updated:


Showing the stock:


Install Vely - you can use standard packaging tools such as apt, dnf, pacman or zypper.

Because they are used in this example, you will need to install Nginx as a web server and MariaDB as a database.

After installing Vely, turn on syntax highlighting in vim if you're using it:

The source code is a part of Vely installation. It is a good idea to create a separate source code directory for each application (and you can name it whatever you like). In this case, unpacking the source code will do that for you:

The very first step is to create an application. The application will be named "stock", but you can name it anything (if you do that, change it everywhere). It's simple to do with vf:

This will create a new application home (which is "/var/lib/vv/stock") and do the application setup for you. Mostly that means create various subdirectories in the home folder, and assign them privileges. In this case only current user (or the result of "whoami" Linux command) will own those directories with 0700 privileges; it means a secure setup.
Before any coding, you need some place to store the information used by the application. First, you will create MariaDB database "db_stock" owned by user "vely" with password "your_password". You can change any of these names, but remember to change them everywhere here. And then, you will create database objects in the database.

Execute the following logged in as root in mysql utility:

In order to let Vely know where your database is and how to log into it, you will create database_config_file named "db_stock". This name doesn't have to be "db_stock", rather it can be anything - this is the name used in actual database statements in source code (like run-query), so if you change it, make sure you change it everywhere. Create it:

The above is a standard mariadb client options file. Vely uses native MariaDB database connectivity, so you can specify any options that a given database lets you.
Use vv utility to make the application:

Note usage of --db option to specify MariaDB database and the database configuration file name.
To start the application server for your web application use vf FastCGI process manager. The application server will use a Unix socket to communicate with the web server (i.e. a reverse-proxy):

This will start 3 daemon processes to serve the incoming requests. You can also start an adaptive server that will increase the number of processes to serve more requests, and gradually reduce the number of processes when they're not needed:

See vf for more options to help you achieve best performance.

If you want to stop your application server:

This shows how to connect your application listening on a Unix socket (started with vf) to Nginx web server.

- Step 1:
You will need to edit the Nginx configuration file. For Ubuntu and similar:

while on Fedora and other systems it might be at:


Add the following in the "server {}" section ("/stock" is the application path (see request_URL) and "stock" is your application name):

- Step 2:
Finally, restart Nginx:

Note: you must not have any other URL resource that starts with "/stock" (such as for example "/stock.html" or "/stock_something" etc.) as the web server will attempt to pass them as a reverse proxy request, and they will likely not work. If you need to, you can change the application path to be different from "/stock", see request_URL.
Use the following URL(s) to access your application server from a client like browser (see request_URL). Use actual IP or web address instead of 127.0.0.1 if different.

Note: if your server is on the Internet and it has a firewall, you may need to allow HTTP traffic - see ufw, firewall-cmd etc.
To access your application server from command line (instead through web browser/web server), use "cgi-fcgi" to see the application response:

Note: to suppress output of HTTP headers, add this before running "cgi-fcgi":

If you need to, you can also run your application as a CGI program.
Execute the following to run your application from command line (as a command-line utility):

Note: to suppress output of HTTP headers, add this before running /var/lib/vv/bld/stock/stock program:

Note: if running your program as a command-line utility is all you want, you don't need to run an application server.
You are now done with the example! What follows are the source files in this project so you can examine how it works:
Table "stock" with stock name and price is created for this example:

This requests (/add-stock) saves the names of stock tickers and their prices. It will obtain the stock name and price from the web client via input-param statement, and then use INSERT SQL to store this data in the database.

You can view stock tickers in a list. SELECT SQL is used to get all the stocks saved so far, and display them in a table using run-query and then query-result to get the query results.

Examples ( example_cookies   example_create_table   example_docker   example_file_manager   example_form   example_hash   example_hello_world   example_json   example_multitenant_SaaS   examples   example_sendmail   example_shopping   example_stock   example_utility   example_write_report  )  SEE ALL (documentation)

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