This plugin fetches the price of a number of common coins used in the Theta Network ecosystem as seen by ThetaScan.io. It allows the user to show the price in US dollar and determine the number of decimal places to display.
It is designed to be used as WordPress shortcode and the results can be seen in the header of this website.
This is also web2 type work. It is 100% dependent upon two servers remaining online.
The Work
The code is an automation for parsing the price functionality using the ThetaScan.io price API. See all their interfaces are documented at the following link.
To see what this plugin parses, place the following URL in your browser and press enter.
http://www.thetascan.io/api/price/
The response from ThetaScan.io looks like this.
{"date":"2022-05-30","theta_price":"1.2490799505828","tfuel_price":"0.06095157509396","VOLT_price":"0.020057886080295","BDOG_price":"0.0089963218653731","BNB.bsc_price":"18.980818840725","BUSD.bsc_price":"1.00","TDROP_price":"0.008536863397248","STABLE_price":"1.00","USDT_price":"1.00","TBILL_price":"1.1869637912051","USDC_price":"1.00","USDC.eth_price":"1.00","WETH_price":"366.21590730422","MTRG_price":"2.1180041814219","WTFUEL_price":"0.06095157509396"}Note that this is JSON data which contains the current prices as seen by ThetaScan.io.
The shortcode in this plugin allows for parsing out any of the data items. The decimal point is considered a special character, thus if you parse out the date, there is no decimal, thus you get the entire date.
Limitations
In the documentation for using ThetaScan API, it says to limit the calls to no more than 1 or 2 per second and that there are two independent servers available to provide robustness to their reliability.
Also, when looking specifically at the price API, they state that they only update the price every 10 minutes. Thus, calling any more often than that would be overkill.
Implemented Solution
In order to not call ThetaScan.io any more than once every 10 minutes, the last call will be stored in the database with the timestamp of when the data was fetched. If an additional call is made by the website within that 10-minute window, the response will simply be read from the database rather than fetching it from ThetaScan.io.
In order to do this, the response will be stored in the WordPress database as a json string. In order to do that, this plugin has a module that interacts with the database. Upon activation and deactivation of the plugin, the database record will be created and removed so as to sandbox the information added.
To keep things simple with regards to the price, the user will be able to specify how many decimal places they want returned for the coin that they are interested in.
The Install
As with any WordPress plugin, unzip the file in the plugin directory.
After placing the file, you’ll need to activate it like you would any other plugin.
Usage
The current proof-of-concept code is a shortcode hook for extracting the data that you want from the ThetaScan.io response. It looks like:
2.14414Tweb2price – this is the shortcode signifier which also matches the plugin name
Item – represents text item in response
Decimals – number of digits right of decimal, but it does not add to the response.
If item is not listed, the code will decode “theta_price”. If decimals is not listed, the default is 4.
Widget
On the right side of the header for that website, I’ve placed the following code in a text widget. As you can see, the shortcode simply returns the number to display. You can format it however you’d like. The following code is also shown just below.
<span style="color: #00ccff;">Theta</span> $[tweb2price decimals=3]
<span style="color: #ff9966;">TFuel</span> $[tweb2price item=tfuel_price decimals=3]
TDrop $[tweb2price item=TDROP_price decimals=3]Code
The basic framework of the Plugin code came from https://wppb.me/. If you generate your own copy with the same plugin name, you’ll be able to compare the files to see where I made changes.
The bulk of the code is in class-tweb2price-shortcode.php and class-tweb2price-record.php. As the naming convention implies, the shortcode handling is separate from the database record & fetch.
Summary
This code is a really simple example of using WordPress’s wp_remote_get() function to call a server to get a response. It also demonstrates how to cache that information in the database in a sandboxed way so as to have a low impact on the WordPress environment.
The framework of this code could be modified to gather and parse out responses from other websites on the internet. If there is one that you’d like to see included in the default plugin, let me know.