This probably could not possibly be a more basic HTTP question, but I am very new to web development and I do not even know the right question to ask (evidenced by the fact that googling has not helped).
What I have: an AWS server with an Elastic Beanstalk environment set up. I have successfully compiled, uploaded, and run a simple "Hello World" program to the environment using Eclipse.
What I want to do: pass the server a number via HTTP request and have the server give me back an HTTP response containing the square of that number. On the back end, I want a simple Java class to do the squaring. (Of course, the goal is to be able to pass more complicated data to the server and have more sophisticated Java code on the back end for processing.)
What I think I need to do: create a Java Servlet to listen for and process the request. I think (hope) the documentation is good enough that I can figure out the HTTPServlet API, but I can't answer a more basic question: how do you pass an HTTP request containing some elementary data, like a number?
Thanks in advance!
You need to either GET, or POST (or PUT) your data. GET provides the data in the URL of the request, and will be displayed in the browser's address bar. POST data is provided as a separate request body.
http://www.w3schools.com/tags/ref_httpmethods.asp
A simple GET would look like this:
http://example.com/server?number=4
You can make a POST using a browser extension such as PostMan:
https://chrome.google.com/webstore/detail/postman-rest-client/fdmmgilgnpjigdojojpjoooidkmcomcm?hl=en
Or you can do it from the command line using curl:
curl -X POST http://example.com/server -d'data'
Once the data is more complicated than a few variables, you probably want to use POST rather than GET. Also, you can start to think about what your requests are doing. GETs should only retrieve data from the server. If you modify or create data, then POST (or PUT) requests are the methods to use.
As your server becomes more complex, you probably want to start reading about REST.
http://en.wikipedia.org/wiki/Representational_state_transfer
Related
I'm looking for a tool to which I can feed a file of saved http requests with their respective headers and the tool executes it. I mean, is there something that does that without the need of creating a wrapper? I know I could easily achieve this in any language, but that's not the question in this case. I know Postman, Insomnia, etc, but not quite sure whether I can open a file with HTTP requests and if so what should be the delimiter per request.
I've read online that you shouldn't update your database with GET requests for the following reasons:
GET request is idempotent and safe
violates HTTP spec
should always read data from a server-database
Let's say that we have build a URL Shortener service. When someone clicks on the link or paste it at the browser's address bar it will be a GET request.
So, if I want to update, on my database, the stats of a shortened link every time it's been clicked, how can I do this if GET requests are idempotent?
The only way I can think of is by calling a PUT request inside the server's side code that handles the GET request.
Is this a good practice or is there a better way to do this?
It seems as you're mixing up a few things here.
While you shouldn't use GET requests to transfer sensitive data (as it is shown in the request URL and most likely logged somewhere in between), there is nothing wrong with using them in your use case. You are only updating a variable serverside.
Just keep in mind that the request parameter are stored in the URL when using GET requests and you should be ok.
I'm hoping this will be a quick answer (probably a 'No').
I have set up a web service on Server B to receive HTTP POST data in JSON format from Server A. I don't have code level access to Server A, but I can manually trigger it to send data to my web service.
My current problem is that I have asked the Server A guys to send me a sample of what is being sent so I can program for the formats etc, but they are taking their sweet time responding.
I know the sending is working, and my WS is responding with my default return string (though Server A is seeing it as an error rather than success .. I don't know what they are expecting back for a successful transmission yet).
I am wondering if it is possible to receive and analyse the data without knowing exactly what is being sent? This way I can start my next phase of coding without needing to wait for them to provide a sample. Plus, I'm not sure how much the format will change for different jobs, so would be good to be able to accept whatever is sent and be able to look at it.
EDIT: To add more background.
Server A is a production application that we use. We have just found out that they have an API that can send data to us (HTTP POST in JSON format) each time one of our users completes whatever they are doing. We want to then store this data to build tables/stats for our clients to view (but that is another story).
You... can try putting together some dummy data, if you know enough about the type of data you'll be getting... But if you don't even know what shape it'll be, I don't know how in the world you would "analyze" it. Unless by "analyze," you mean get the size or something generic like that...
Is it possible, with TcpCatcher to send an HTTP request from a custom hook (a Java class)? I know the GUI let someone edit and resend any given request, but I want this process to be automatic on certain conditions (and log the results, etc.)
So, I know it's possible, but no documentation for it. I'm asking if anyone had done this, or know how to do this? I'm looking at the tcpcatcher.jar file, but many classes are named a.class, b.class, etc. So if the knowledge exists somewhere around this community, it would be great.
TcpCatcher allows you to provide your own java class and calls it when an HTTP packet goes though the proxy.
You can do anything within the hook including sending an other HTTP request (but why would you want do that by the way ?)
Here is an example of a synchronous hook (it allows you to modify the packet on the fly)
http://www.tcpcatcher.org/hook_to_change_html.php
just implement the "modifyPacket" method
If you do not intend to modify the packet on the fly, you can prefer an asynchronous hook.
Here is an example :
http://www.tcpcatcher.org/logging.php
This is more of an issue of trying to understand how HTTP really works and then implementing it.
I need to have a HTTP analyzer that will be able to separate between the main page requests and "background" requests from some HTTP log data. The idea is to separate HTTP requests made by the user from those that happen automatically (loosely using this term) in the background. So, from the first few impressions of the HTTP data that I've seen it seems like when I go to any normal website an text/html object is fetched followed by a lot of other objects like css, xml, javascript, images etc.
Now, the problem is how do I separate these "background" requests where the user is actively not generating the requests. This will mostly be ad fetches, redirections and some Ajax based things from what I know.
Does anyone has any idea with regards to this. Some, experience or may be resources that you could point me to get started with doing this analysis?
There's no way to distinguish which requests were generated by the browser because of specific user actions or because of other automated processes from the bare HTTP requests. The browser/client it the only one that has such knowledge, so that you have to make it part of the picture, e.g. implementing the analyzer as a browser plugin or to embed an HTTP client as part of the analyzer itself.
If you're trying to create a generic tool to analyze traffic load, it's usually not meaningful to distinguish between traffic generated by user's direct "clicks" and automated requests.
There's no direct and clean way to do this. However, you can get pretty close by filtering out requests for files that clearly are not "user" requests, like *.jpg. Furthermore, you can filter out what is not a HTTP/200 response (e.g., 301 and 302 redirects).
Try something along the lines of:
cat access.log
| grep -E -v "(.gif|.ico|.png|.jpg|.jpeg|.js|.css) HTTP"
| grep "HTTP/1.1\" 200"
(added line breaks for readability)