If I understand HTTP requests correctly, they come from the client side and ask the server for the various resources needed to build the website. If this is true, is there a way to use server-side scripts to bundle everything the visitor needs in order to reduce HTTP requests?
Am I misunderstanding the way HTTP requests work?
Is there a drawback to this?
There are several techniques:
you can bundle several of your ressource in a single file, exemple, all css, javascript, etc...
you can send multiple files in one:http pipelining
http 1.1 reuse the connection so this reduce also the request/response time....
Related
i am taking a course in web data so i understand that when we want to retrive a webpage on a browser we do a request response cycle using a communication protocol like http or https and a web service is a piece of software which i dont know where it is stored or how it is accessed so we can make two applications from different architectures communicate using a serialization language like XML or JSON i dont know what is the difference between a web service and http they are both a way to connect 2 different computers together and what confused me the more is api which according to the research i did is something used to access web services.
Let's begin with defining all the terms in your question since it's a bit all over the place.
HTTP (Hypertext-Transport Protocol): Allows you to transfer data over the web. Your browser will perform a request using HTTP to your web service.
Service: Any software that performs a specific task. We are interested in a web service, which is typically invoked via HTTP, however this can be anything else such as a Linux signal.
For now, let's assume it listens on HTTP.
API (Application Programming Interface): An interface by which all clients of your software have to abide by to use it. For example, in our web service, we can dictate an API so requests follow some convention.
Let's put it all together now.
You're making a website that wants to calculate the sum of two numbers. First, users will go to http://yoursite.com, and then the browser will always do an HTTP request to the domain yoursite.com on port 80. This will hit either your hosting site or some backend server.
Here you have the option if you're using something like GitHub pages to serve static content or you have some server (i.e., serverd) that will load a file and serve it.
So now the web-browser did an HTTP request and your webpage should load with an index.html. The user can now click on buttons, and everything looks good until they press Calculate -- what happens now?
We want to offload the computation to our backend. We perform an HTTP request to our backend server. We can define an API, that is in our case an endpoint, so that the HTTP request can hit it and it'll return the sum of the two numbers.
How do we return the result? We need to represent the data somehow, and this can be done through a body payload that is encoded as either JSON or XML. Again, this is a serialization format and can encode it in various different ways. JSON is nice because you can parse it easily with JavaScript on the client side.
Great -- so now we got an entire site and it works! Now we can do an HTTP request from our browser straight to the backend according to our setup endpoint and it should fulfill our request. Notice how now we're using the API from the backend server from within our site.
Other keywords you can may run into: CORS, AJAX, Apache Server; good luck!
We wish to build a web app that will consume our REST API and looking for a way to circumvent the Same Origin Policy security feature.
We have a REST API which is served from api.ourdomain.com from SERVER_1.
We have a Web App which is server from dashboard.ourdomain.com from SERVER_2.
The Web App communicates with the REST API using ajax calls that include GET, POST, DELETE and PUT requests.
At some point in the future, we might consider allowing 3rd party sites to access the API from their own sites and domains.
Due to the Same Origin Policy security feature of the browsers, these requests are not allowed.
We are looking for ways to circumvent this.
Solutions we have encountered:
Tunneling the requests through our proxy. This will slow down the app and requires more resources.
JSONP - Will only work for GET requests. We do not wish to overload the GET requests with post/put/delete capabilities.
Using an iFrame with document.domain set to the same domain. Will only work for sites under ourdomain.com.
Frameworks such as EasyXDM. Seems like a good solution.
Thank you!
I don't know EasyXDM but I have the same architecture you are talking about in more than one application. We use your suggested solution (1). In my opinion proxying the requests through a common subdomain is the cleanest solution. I don't think that this is a performance problem. Many sites use something like nginx anyway to do some sort of reverse proxy (as cache). You could easily tunneling your API through http://[yourhost]/api and the rest of the HTML, CSS and image resources through other paths.
I searched some of the similar questions, but haven't had a right solution yet.
I need to test a web cluster (which consists of many nodes, to provide some set of REST-ful APIs).
Not only HTTP GET request, I need to generate dynamic POST/PUT request in some manners. There are many tools, but I couldn't find right tool for generating POST/PUT request with non-static data.
Since I need to generate quite a large amount of requests, the load test tool should run in distributed nodes. In shorts:
ability to write the custom request for HTTP GET, POST and PUT. (any kind of major language such as Java, Ruby, etc. is okay)
ability to works in distributed Linux environment. (i.e. use multiple nodes to generate the requests)
ability to works on both HTTP and HTTPS
optional: generating nice-looking graphs
optional: construct a new request and queue for later (for state-ful API testing)
Based on certain condition, the request generator needs to parse JSON document in the HTTP body, and process it to make another GET/POST/PUT request.
Checkout Tsung, Faban, and Rain. Most likely, you have to edit some scripts within their frameworks.
I have a service that always returns the same results for a given parameter. So naturally I would like to cache those results on the client.
Is there a way to introduce caching and other effect inside the WCF pipeline? Perhaps a custom binding class that could site between the client and the actual HTTP binding.
EDIT:
Just to be clear, I'm not talking about HTTP caching. The endpoint may not necessarily be HTTP and I am looking at far more effects than just caching. For example, one effect I need is to prevent multiple calls with the same parameters.
The WCF service can use Cache-Control directives in the HTTP header to say the client how it should use the client side cache. There are many options, which are the part of HTTP protocol. So you can for example define how long the client can just get the data from the local cache instead of making requests to the server. All clients implemented HTTP, like all web browsers, will follow the instructions. If your client use ajax requests to the WCF server, then the corresponding ajax call just return the data from the local cache.
Moreover one can implement many interesting caching scenarios. For example if one set "Cache-Control" to "max-age=0" (see here an example), then the client will always make revalidation of the cache by the server. Typically the server send so named "ETag" in the header together with the data. The "ETag" represent the MD5 hash or any other free information which will be changed if the data are changed. The client send automatically the "ETag", received previously from the server, together inside the header of the GET request to the server. The server can answer with the special response HTTP/1.1 304 Not Modified (instead of the typical HTTP/1.1 200 OK response) and with the body having no data. In the case the client will safe to get the data from the local cache.
I use "Cache-Control:max-age=0" additionally with Cache-Control: private which switch off caching the data on the proxy and declare that the data could be cached, but not shared with another users.
If you want read more about caching control with respect of HTTP headers I'll recommend you to read the following Caching Tutorial.
UPDATED: If you want implement some general purpouse caching you can use Microsoft Enterprise Library which contains Caching Application Block. The Microsoft Enterprise Library are published on the CodePlex with the source code. As an alternative in .NET 4.0 you can use System.Runtime.Caching. It can be used not only in ASP.NET (see here)
I continue recommend you to use HTTP binding with HTTP caching if it only possible in your environment. In the way you could save many time of development and receive at the end more simple, scalable and effective application. Because HTTP is so important, one implemened already so much useful things which you can use out-of-the-box. Caching is oly one from the features.
The question is as simple as the title. I have a webapp (I have no clue as to what technology it was built on or what appserver it is running on). However, I do know that this webapp is being served by an Apache Server/ IIS Server / IBM Http Server. Now, I would like to have a plugin/ module / add-on at the web-server end, which would parse/truncate/cut/regex the http response (based on the requested url's pattern), and mask(encrypt/shuffle/substitute) a set of fields in this response based on different parameters(user's LDAP permissions in the intranet / user's geo-location if on the internet, etc) and send the altered response back to the user.
So, Is there an easy answer to creating such plugins/modules/add-ons? How feasible is this approach of creating extra software at the webserver, when you want to mask sensitive information in a webapp without modfying the web-app code? Are there any tools that help you do this for Apache?
And, finally, is this just a really crazy thing to try?!
Each webserver will have its own way of doing so.
There is no universal plugin architecture for webservers.
In IIS you would write an HTTP Handler or HTTP Module, or possibly an ISAPI Filter. You can also directly interact with the http response using the Response object exposed by the HttpContext.
With apache, there are different modules that can do what you want (mod_headers, for example).
I don't know anything about WebSphere, but I am certain it also has similar mechanisms.
What you are asking is required by most web applications, so would be either built in or very easy to do.
The easiest way is to add a plug-in using the web application container. For example, if it's Tomcat, you can add a filter or valve.
If you want to plug-in to the web server, you'd need to write a custom module using the API of whichever web server is being used.
If all else fails, you could always wrap the entire server in a reverse proxy. All requests would go through your proxy and that would give you the opportunity to modify the requests and the responses.