I want to use the Stack Exchange API to perform research on the question/answer's body but it seems impossible.
Is that the case? If not, how do I go about doing it?
In order to access the body of a post, you need to create a filter that includes this information. You create a filter using the /filters/create method:
http://api.stackexchange.com/2.0/filters/create?include=question.body;answer.body
The response from that URL will look something like this:
{
"items": [{
"filter":"!9Tk5izFWA",
...
}
As you can see, the new filter is identified by the string !9Tk5izFWA. You need to then pass this as the filter parameter to any request that you want to obtain the post body on.
Example:
http://api.stackexchange.com/2.0/questions?site=stackoverflow&filter=!9Tk5izFWA
Edit: upon further clarification, the method you are looking for is /search. The example would now become:
http://api.stackexchange.com/2.0/search?site=stackoverflow&filter=!9Tk5izFWA&intitle=java
This example will search for all questions that contain the string "java" in the title.
In the 2.2 version of the API a new end-point /search/advanced got added.
Search the site for questions using most of the on-site search options.
That API does take a body parameter, allowing you to find only questions with a certain term in the body.
Here is how you use it to find questions with the word search in it:
The items array returns instances of the question type.
Unfortunately it will not return answers.
/search/advancedroute, added in API version 2.1, allows you to search on question bodies (not answers, alas) using theqparameter.