I am using libcurl in C to retrieve data from a server. I am caching the initial connection to be used again and again for further retrieving from the server. But, i also want the GET or POST question to be asked each time I ask for a response from the server.. Any workaround this?
There's no "workaround" needed, you simply set the correct options for each transfer you want and libcurl will use GET or POST correctly. It will still reuse the connection if you reuse the curl handle and the server doesn't close it...
CURLOPT_POSTFIELDS is a common option to set POST (with data) and then you reset it back to use GET with CURLOPT_HTTPGET.
Related
I have a page with multiple widgets, each receiving data from a different query in the backend. Doing a request for each will consume the limit the browser puts on the number of parallel connections and will serialize some of them. On the other hand, doing one request that will return one response means it will be as slow as the slowest query (I have no apriori knowledge about which query will be slowest).
So I want to create one request such that the backend runs the queries in parallel and writes each result as it is ready and for the frontend to handle each result as it arrives. At the HTTP level I believe it can be just one body with serveral json, or maybe multipart response.
Is there an angularjs extension that handles the frontend side of things? Optimally something that works well with whatever can be done in the Java backend (didn't start investigating my options there)
I have another suggestion to solve your problem, but I am not sure you would be able to implement such a thing as from you question it is not very clear what you can or cannot do.
You could implement WebSockets and the server would be able to notify the front-end about the data being fetched or it could send the data via WebSockets right away.
In the first example, you would send a request to the server to fetch all the data for your dashboard. Once a piece of data is available, you could make a request for that particular piece and given that the data was fetched couple of seconds ago, it could be cached on the server and the response would be fast.
The second approach seems a more reasonable one. You would make an HTTP/WebSocket request to the server and wait for the data to arrive over WebSocket.
I believe this would be the most robust an efficient way to implement what you are asking for.
https://github.com/dfltr/jQuery-MXHR
This plugin allows to parse a response that contains several parts (multipart) by having a callback to parse each part. This can be used in all our frontends to support responses for multiple data (widgets) in one requests. The server side will receive one request and use servlet 3 async support (or whatever exists in other languages) to ‘park’ it, sending multiple queries, writing each response to the request as each query returns (and with the right multipart boundary).
Another example can be found here: https://github.com/anentropic/stream.
While both of these may not be compatible with angularjs, the code does not seem complex to port there.
I want to make a database query from frontend (Angular) to backend. But I need to send lots of parameters for that.
As far as I understand, if we are not making any database changes, it is better to use GET as it uses cached entries. POST should be used used if we need to make changes on server/DB.
But if I want to send many parameters (some are serialized objects) and make no server side changes, will it be alright to use POST request in that case and embed all parameters in the POST body instead of sending a huge URL encoded GET request?
To first clear this up: responses to POST requests can be cached, as long as the origin server returns the proper caching response headers. However, browsers and proxy servers generally don't apply caching to POST requests.
That being said, with the proper encoding you can store a lot of information in the ~ 2 KB of a query string, so GET should be the way to go.
If you're certain you'll go beyond the limits of a GET request and you'll need to go the POST way while remaining cacheable, you could introduce a kind of "nonce", for example using a hash of the search parameters:
Client does a POST to /search, with the search parameters.
Server stores the parameters somewhere, for example in a database.
Server generates a nonce from the parameters, for example by hashing the search parameters, or the row ID.
Server redirects the client to the result page for that nonce: /search/123abc.
Client requests the /search/123abc search results page.
Server performs the search based on the nonce, and returns a response which is cacheable.
This will introduce one additional HTTP roundtrip, but enable caching cross-browser and through proxy servers.
I think you should use post in this situation which is more manageable and looks clean. For more benefit of post follow these links:
Link 1
Link 2
I have a standard build of Apache running on Ubuntu 12.04 with PHP 5.3.10.
I'm looking to have a REST server running on it but I ran into problems. For now there is one index.php which is doing a print_r($_POST);
By using this tool https://chrome.google.com/webstore/detail/advanced-rest-client/hgmloofddffdnphfgcellkdfbfbjeloo/ I am posting data to the page. If I set the data to be sent as x-www-form-urlencoded then the $_POST variable is populated.
However, if I set the data to be sent as application/json the $_POST variable isn't populated, but the raw data is available in HTTP_RAW_POST_DATA.
The reason I am testing in in this way is this is the same behaviour I am seeing when I am running the REST server (https://github.com/philsturgeon/codeigniter-restserver). So i think this must be an Apache problem.
HAs anyone else had this issue? I dont have much experience with running REST servers so it may well be something I am doing wrong.
That is how it suppose to be. however if you want the posted data you can
$postdata = json_decode(file_get_contents("php://input"), true);
I got an assignment to do and for that I could use any www technology like HTML, JavaScript, PHP etc. I'm really sorry to say that I haven't studied any of these technologies. Therefore I took few tutorials and skimmed through them searching for answers.
I found solutions for many problems but one problem yet unsolved. It is this:
I want two clients to communicate through a server for this assignment. One send a message, server processes it and forwards it to the next.
None of PHP tutorials showed me anyway of doing this. All of them talked of communication between one client with a server.
Please help. Show me a way to do this. Thanks.
Currently, without reverting to cutting-edge (and possibly hacky/unreliable) techniques, your PHP server cannot initiate communications with a page you've already loaded into a web browser. This is a result of the way the HTTP protocol works.
One way to solve this would be polling on the "receiving" end for data. Something like a publish-subscribe pattern.
One way to do this would be:
One client sends data to the server using an HTTP request (XHR aka AJAX) specifying the target for this data (the other client).
The server stores this data in a persistent storage (local file, database, etc).
The second client periodically sends a request to the server asking if there's any new data for it to consume. This can be done using setInterval and XHR in JavaScript.
I would suggest you take a look at:
http://en.wikipedia.org/wiki/Publish/subscribe
And also, for a cutting edge way to do this, check out Socket.IO:
http://socket.io
You might want to Google on "php chat server." Building a chat server is a simple way to get started.
http://net.tutsplus.com/tutorials/javascript-ajax/how-to-create-a-simple-web-based-chat-application/
http://code.jenseng.com/jenChat/
Iam writing a C program to interact with HTTPs server. Server is expecting the data without
any assignments(Ex: normally a request can be "https://xz.aspx?name=google" where as is it
possible to send the name "https://xz.aspx?google"). Currently server is getting an entry
log for my request but not able to fetch request data.
1.Is it possible to send a value with out assignment?
2.Will .net look for default assignments?
3.Is there anything else to probe?
The data you're sending is just whatever you put in the query part of the request-uri in the HTTP request.
That data can be almost anything you like (as long as it is using letters that are valid according to RFC2616). The "assignments" concept is not something HTTP knows or uses, it is just a common way for clients and servers to deal with the data.
so... Yes, you can send a value "without assignment" with curl. Weather the receiver will like it or understand it is a completely different matter.