How can i extract data out of software (trading platform) in real-time and save it so that it can be analyzed later?
Do i need some kind of API ? What is an API exactly (i'm not very clear on it) ?
Do I need to know the programmer of the software (trading platform) to get that API ?
Plz, suggest some literature to get me started too.
How can i extract data out of software (trading platform) in real-time and save it so that it can be analyzed later?
You can use API or output logs if software provides it actually.
Do i need some kind of API?
It would be great (and again if such API available)
What is an API exactly
programming interface for communication with target software (as Niels mentioned)
Do I need to know the programmer of the software (trading platform) to get that API ?
You should get documentation about API for target software and if it's not available you should ask about that from developers of target software.
I wasn't going to submit an answer since the other answers are pretty much dead on. I just felt like they lacked something.
API
An API is essentially a way for a piece of software to transmit data to another piece of software without any issues. There are multiple different types of APIs and there is a lot more APIs than you likely realize. Personally, I believe most every functional piece of software should be powered by or have an API of some sort.
RESTful APIs use HTTP requests (GET,POST etc) in order to transmit and recieve data. They are a newer version of APIs and typically use JSON as their formatting. These APIs are extremely quick and simply intake a request and submits a response. These APIs can sometimes include what is called a WADL. A WADL will be consumed and allows the user to more easily interact with the API.
A WSDL based API uses XML to interact with another system. These APIs are slowly being phased out for public facing systems since they typically have a higher overhead, require larger packets and consume more resources. I have yet to see much of a drop in popularity in back-end based systems though.
Interacting with your API
Testing
Depending on the type of API, the first step is to consume the web service if the developer provided a WSDL or WADL. The easiest way to perform such a task, especially for testing, is to use a tool like SoapUI. If there is no WSDL or WADL provided, for REST based APIs it will create the request based on the URLs. After that you can interact with the API by transmitting data and receiving the results.
For further information on SoapUI please feel free to google search and if you still have any specific questions, ask a new question.
Developing
Once you have an understanding of your API, the expected results and know what is supposed to be input and the expected output the fun can begin. I will stick with a WSDL based API and assume C#. Java is rather simple to use as well though.
In C# with VS you can use what is called "Add Service Reference" to interact with an API. After that, put in the URL to your WSDL and all of the functions are magically created. Make the calls that you need to make to the API and the data that you need will be in the response. Parse it how you need it to be done and your application now interacts with the API.
The point of an API is simplicity and flexibility
They are designed to allow another system to interact with the system that is running it. They are usually designed to be language agnostic and should be easily consumable and easy to interact with. Using a tool like SoapUI will help you a lot along the way.
API stands for Application programming interface
In computer programming, an application programming interface (API) is a set of routines, protocols, and tools for building software applications.
Some programs have an API which you can use to write software against, you can then utilize predefined functions available in the platform. I would guess a trading platform would have an API to retrieve data and or to place orders.
Often the API is clearly documented with examples how to use it. The supplier delivers the needed information normally. Thus YES you need to contact the developers of the API to find how it works and what features it supports.
See this link about an example API and its usage.
While trading application testing we use various technique to get output of software to check whether our application is working as expected or not. Yes, You can save the API's logs and investigate them later if there is an API provided by software. Moreover, If trading platform software provide API's then they will provide you documentation for the same. However , we can print the logs for each action performed in software and investigate those logs. If the logs are also not provided then using visual comparison tools like Applitools we can extract the data.
