I am working on an ISAPI Filter to strip certain content out of responses. I need to collect all the body of the response before I do the processing, as the content I'm stripping could overlap send buffers.
To do this I'd like to buffer the response content with each SF_NOTIFY_SEND_RAW_DATA notification until I get to the last one, then send the translated data. I would like to know the best way to determine which SF_NOTIFY_SEND_RAW_DATA is actually the last. If I wait until the SF_NOTIFY_END_OF_REQUESTnotification, then I don't know how to send the data I've buffered.
One approach would be to use the content-length. This would require I detect the end of the headers. It would also require assuming the content-length header is correct (is that guaranteed?). Since HTTP doesn't even require a content-length header, I'm not even sure it will always be there. There seems like there should be an easier way.
I'm assuming the response is not chunked, so I am not handling dechunking before I do the response change. Also, when I do the modifications to the response body, the size of teh response body will not change, so I do not need to go back and update the content-length.
I eventually found some good discussions via google.
This posts answers my questions, as well as raises issues a more complicated filter would have to address: http://groups.google.com/group/microsoft.public.platformsdk.internet.server.isapi-dev/browse_thread/thread/85a5e75f342fad2b/cbb638f9a85c9e03?q=HTTP_FILTER_RAW_DATA&_done=%2Fgroups%3Fq%3DHTTP_FILTER_RAW_DATA%26start%3D20%26&_doneTitle=Back+to+Search&&d&pli=1
The filter I have s buffering the full request into its own buffer then using the SF_NOTIFY_END_OF_REQUEST to send the contents. The modification it does does not change the size, and precludes the possibility that the response is chunked, so in my case the filter is relatively simple.
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I havent find ressources online to solve my problem.
I'm creating an app with React Native that fetches and shows news articles from my database.
At the top of the page, there's some buttons with filters inside, for example:
one button "energy",
one button "politics"
one button "people"
one button "china"
etc...
Everytime I press one of those buttons, the filter corresponding is stored in an array "selectedFilters", and I want to fetch my database to only show articles that are corresponding to those filters.
Multiple filters can be selected at the same time.
I know one way of doing it, with a POST request:
await fetch('187.345.32.33:3000/fetch-articles', {
method: 'POST',
headers: {'Content-Type':'application/x-www-form-urlencoded'},
body: 'filters=${JSON.stringify(selectedFilters)}'
});
But the fact is, I read everywhere, and I also was teached, that POST request are used when creating or removing, and theoretically, what I should use is a GET request.
But I don't know how to send an Array with GET request.
I read online that I can pass multiple parameters to my url(for example: arr[0]=selectedFilters[0]&arr[1]=... but the fact is I never know in advance how many items will be in my array.
And also I'm not sure if I could write exactly the same way as my POST request above, but with GET:
await fetch('187.345.32.33:3000/fetch-articles', {
method: 'GET',
headers: {'Content-Type':'application/x-www-form-urlencoded'},
body: 'filters=${JSON.stringify(selectedFilters)}'
});
or if I can only pass items in the url, but does this work ?
await fetch('187.345.32.33:3000/fetch-articles?arr[0]=${selectedFilters[0]', {
Or even better if something like this could work:
await fetch('187.345.32.33:3000/fetch-articles?filters=${JSON.stringify(selectedFilters)}', {
Thanks for your help
You should definitely use a GET request if your purpose is to fetch the data.
One way of passing the array through the URL is by using a map function to create a comma separated string with all the filters. This way you would not need to know in advance how many elements are in the array. The server can then fetch the string from the URL and split it on the commas.
One more method you can try is to save a filters array on the server side for the session. You can then use a POST/PUT request to modify that array with new filter as user adds or remove them. Finally you can use an empty GET request to fetch the news as the server will already have the filters for that session.
But the fact is, I read everywhere, and I also was teached, that POST request are used when creating or removing, and theoretically, what I should use is a GET request.
Yes, you do read that everywhere. It's wrong (or at best incomplete).
POST serves many useful purposes in HTTP, including the general purpose of “this action isn’t worth standardizing.” (Fielding, 2009)
It may help to remember that on the HTML web, POST was the only supported method for requesting changes to resources, and the web was catastrophically successful.
For requests that are effectively read only, we should prefer to use GET, because general purpose HTTP components can leverage the fact that GET is safe (for example, we can automatically retry a safe request if the response is lost on an unreliable network).
I'm not sure if I could write exactly the same way as my POST request above, but with GET
Not quite exactly the same way
A client SHOULD NOT generate content in a GET request unless it is made directly to an origin server that has previously indicated, in or out of band, that such a request has a purpose and will be adequately supported. An origin server SHOULD NOT rely on private agreements to receive content, since participants in HTTP communication are often unaware of intermediaries along the request chain. -- RFC 9110
The right idea is to think about this in the framing of HTML forms; in HTML, the same collection of input controls can be used with both GET and POST. The difference is what the browser does with the information.
Very roughly, a GET form is used when you want to put the key value pairs described by the submitted form into the query part of the request target. So something roughly like
await fetch('187.345.32.33:3000/fetch-articles?filters=${JSON.stringify(selectedFilters)}', {
method: 'GET'
});
Although we would normally want to be using a URI Template to generate the request URI, rather than worrying about escaping everything correctly "by hand".
However, there's no rule that says general purpose HTTP components need to support infinitely long URI (for instance, Internet Explorer used to have a limit just over 2000 characters).
To work around these limits, you might choose to support POST - it's a tradeoff, you lose the benefits of safe semantics and general purpose cache invalidation, you gain that it works in extreme cases.
Far as I understand, PUT request is not supposed to return any content.
Consider the client wants to run this pseudo code:
x = resource.get({id: 1});
x.field1 = "some update";
resource.put(x);
x.field2 = "another update";
resource.put(x);
(Imagine I have an input control and a button "Save", this allows me to change a part of object "x" shown in an input control, then on button click PUT changes to server, then continue editing and maybe "save" another change to "x")
Following different proposals on how to implement optimistic locking in REST APIs, the above code MUST fail, because version mark (however implemented) for "x" as returned by get() will become stale after put().
Then how do you people usually make it work?
Or do you just re-GET objects after every PUT?
You can use "conditional" actions with HTTP, for example the If-Match header described here:
https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.24
In short: You deliver an ETag with the GET request, and supply this ETag back to the server in the If-Match header. The server will respond with a failure if the resource you are trying to PUT has another ETag. You can also use simple timestamps with the If-Unmodified-Since header.
Of course you will have to make your server code understand conditional requests.
For multiple steps, the PUT can indeed return the new representation, it can therefore include the new ETag or timestamp too. Even if the server does not return the new representation for a PUT, you could still use the timestamp from the response with an If-Unmodified-Since conditional PUT.
Here is probably what I was looking for: https://www.rfc-editor.org/rfc/rfc7231#section-4.3.4
They implicitly say that we CAN return ETag from PUT. Though only in the case server applied the changes as they were given, without any corrections.
However this raises yet another question. In real world app PUT caller will run asynchronously in JS gui, like in my example in the question. So, Save button might be pressed several times with or without entering any changes. If we don't use optimistic locking, then supposed PUT idempotency makes it safe to send another PUT query with each button click, as long as the last one wins (but actually if there were changes then it's not guaranteed, so the question remains).
But with optimistic locking, when first PUT succeeds, it returns updatred ETag, ok? And if there is another PUT request running, still with outdated tag version, that latter request will get 412 and the user will see a message "someone else changed the resource" - but actually it was our former changes.
What do you usually do to prevent that? Disable the Save button until its request is fully completed? What if it times out? Or do you think it's acceptable to see concurrent-change error message if it was a timeout, because the stability is already compromised anyway?
I have a camel route which processes xml data and send to http endpoint. below is my http endpoint.
.recipientList(simple("http://${header.httpUri}?xmlData=${body}"))
where the httpUri ill get it from db hence set it header and used. Body contains xml data with special characters of different language. Whenever it tries to resolve endpoint, since the body contains special characters, ResolveEndpointException occurs. The tracer log shows the body with special characters resolved like %20B etc.,
I feel the problem is with simple() SimpleBuilder.
Is there any other way to resolve endpoint dynamically???
Tried POST, HTTP_URI and HTTP_QUERY. It didnt work. Then found it was related to character encoding. My request contained some ISO-8859-9 encoding data. I send request with character encoding ISO-8859-9, and it worked.
I'd like to get raw messages for a particilar thread via "Users.threads: get" request. Is it possible to use format=raw parameter in this request somehow? I know it is possible for message request but I really need to do that for this one.
It might be useful to specify the format (raw or minimal) when requesting a thread, unfortunately this is not currently possible. The format can only be set for a message request. Requesting a thread in raw format however would not be a good idea since a thread could contain many large messages.
It is possible to set the format, but for some reason google doesn't allow the raw format when getting threads.
See the docs here
It's regarding content length.
I know its use. It tells the receiver that "this much" data I am sending.
It's available with both request & response. In Java, we have setContentLength() method for response, we can set content length to some value using this method and browser is going to read only up to that point in the body.
In request, we don't have any setContentLength() method - at least not in Java. So I believe browser sets this as per the data request is containing. Now let’s say if I modify this request in between – change a parameter value to some bigger value, how do I change the content length? If I don’t change content length, server doesn’t read the complete body – it only reads up to content length & ignores rest of the body content.
I hope my question is clear.
Thanks.
PS: I am changing request in a C filter in web server before request goes to application server.
I'm not sure if it's a good idea to change content length of request, I don't think you can achieve that simply, the only way i can think of is parse the content of request, the strip unneeded data and the generate the request that simple mimics original request but contains stripped data, it also depends on the whenever you are using POST or GET requests