I would like to modify the response body returned by the backend.
As background I'll detail my specific problem (but I don't require a solution to the specific problem, just the method for manipulating a response body). I want to insert/add a key value pair to the response body based on the status code of the response and I want to transform snake_case keys into camelCase keys.
For example, given a response with
status code: 401
body: {'detail_message': 'user is not logged in'}
I want to transform it to a response with
status code: 401
body: {'success': False, 'detailMessage': 'user is not logged in'}
The rule for success would be True for anything below 400 and False for anything above or equal.
Lua scripting can be used in my API gateway which is Krakend
https://www.krakend.io/docs/endpoints/lua/
The documentation only includes examples for printing the response body and modifying headers but not for modifying the response body.
I have no experience with Lua and only need it for one task. I haven't been able to find online example of response body manipulation which I could play with.
What methods do I need in order to add a key value pair to a response body and to manipulate the keys in the response body?
How I get original bytes from request? Calling request.body.asBytes() I get this message:
asBytes() expected list of bytes, instead got List<_InternalLinkedHashMap<String, dynamic>>
I saw that HTTPRequestBody has the property retainOriginalBytes to use in this case, but where I set it?
Thanks!
Whatever endpoint you're hitting with your request is returning a Map in its body, not a list of Bytes.
I'm not sure if you can control the contents of what that endpoint is returning but if you can that would be the place to change it.
Check out the BytesBuilder class. Also, read the Aqueduct docs for Request and Response Objects. Hopefully this gets you on the right path!
You're on the right track; this will work correctly once you've set retainOriginalBytes to true. This must be done before the body is decoded.
In an HTTPController, the request body is decoded before your method that handles the request is called. Just before the decoding, HTTPController calls its willDecodeRequestBody() method. This method does nothing by default, but you can override it to set retainOriginalBytes:
#override
void willDecodeRequestBody(HTTPRequestBody body) {
body.retainOriginalBytes = true;
}
Here is an example of an application that does this.
I have a Grails controller that receives a DefaultMultipartHttpServletRequest like so:
def myController() {
DefaultMultipartHttpServletRequest proxyRequest = (DefaultMultipartHttpServletRequest) request
}
This controller acts as a proxy by taking pieces of this request and then resends the request to another destination.
For non-multipart requests, this worked fine, I did something like:
IProxyService service = (IProxyService) clientFactory.create()
Response response = service.doPOST(proxyRequest.getRequestBody())
Where proxyRequest.getRequestBody() contains a JSON block containing the request payload.
However, I do not know how to get this to work with multipart request payload, since the request body is no longer a simple block of JSON, but something like the following (taken from Chrome devtools):
How can I can pass this request payload through using my proxy service above, where doPost takes a String?
Have you tried
def parameterValue = request.getParameter("parameterName")
to get the parameter value?
If you see the method signatures for DefaultMultipartHttpServletRequest you will see there are methods for getting the files and other parameters separately because the request body is getting used to both upload the file and to pass in other parameters.
In Delphi, I'm using Indy's TIdHTTPWebBrokerBridge coupled with TIdHTTP to send/receive data via HTTP. On the Server, I don't have any fancy handling, I always just respond with a simple content stream. If there's any issues, I only return information about that issue in the response content (such as authentication failed, invalid request, etc.). So, on the client side, can I assume that every successful request I make to this server will always have a response code of 200 (OK)?
I'm wondering because on the client, the requests are wrapped inside functions which return just a boolean for the success of the request.
Inside this function:
IdHTTP.Get(SomeURL, AStream);
Result:= IdHTTP.ResponseCode = 200;
This function handles any and every request which could possibly fetch data. If there were any issues in the request, This function should return False. In my scenario, since I always return some sort of content on the server, would the client always receive a response code of 200 in this function?
I guess the real question is, if I always return some sort of content and handle all exceptions on the server, then will the server always return status code of 200 to each request?
"Does every successful HTTP request always return status code 200?"
See w3.org: HTTP/1.1 Status Code Definitions (RFC 2616)
The answer is No. All 2xx are considered successful.
That may depend on the HTTP method used.
Should your web-server application always return 200 upon success? That may as well depend on the request method and the signal it intends for the client . e.g.
for PUT method (emphasis is mine):
If an existing resource is modified, either the 200 (OK) or 204 (No
Content) response codes SHOULD be sent to indicate successful
completion of the request.
for POST method:
The action performed by the POST method might not result in a resource
that can be identified by a URI. In this case, either 200 (OK) or 204
(No Content) is the appropriate response status, depending on whether
or not the response includes an entity that describes the result.
If a resource has been created on the origin server, the response
SHOULD be 201 (Created) and contain an entity which describes the
status of the request and refers to the new resource, and a Location
header (see section 14.30). Responses to this method are not
cacheable, unless the response includes appropriate Cache-Control or
Expires header fields. However, the 303 (See Other) response can be
used to direct the user agent to retrieve a cacheable resource.
As you can learn from the RCF, every method SHOULD have it's own success status codes, depending on the implementation.
Your other question:
"can I assume that every successful request I make to this server will always have a response code of 200 (OK)?"
You can always expect Status code 200, if your web server always responds with Status 200. Your web server application controls what response it returns to the client.
That said, Status code 200 is the Standard response for successful HTTP requests (The actual response will depend on the request method used), and in the real world of web servers, SHOULD be set as default upon successful request, unless told otherwise (As explained in Remy's answer).
To answer your specific question:
can I assume that every successful request I make to this server will always have a response code of 200 (OK)?
The answer is Yes, because TIdHTTPWebBrokerBridge wraps TIdHTTPServer, which always sets the default response code to 200 for every request, unless you overwrite it with a different value yourself, or have your server do something that implicitly replies with a different response code (like Redirect() which uses 302, or SmartServeFile() which uses 304), or encounter an error that causes TIdHTTPServer to assign a 4xx or 5xx error response code.
However, in general, what others have told you is true. On the client side, you should handle any possible HTTP success response code, not just 200 by itself. Don't make any assumptions about the server implementation.
In fact, TIdHTTP already handles that for you. If TIdHTTP encounters a response code that it considers to be an error code, it will raise an EIdHTTPProtocolException exception into your code. So if you don't get an exception, assume the response is successful. You don't need to check the response code manually.
If there is a particular response code that normally raises an exception but you do not want it to, you can specify that value in the optional AIgnoreReplies parameter of TIdHTTP.Get() or TIdHTTP.DoRequest(). Or, if you are are using an up-to-date Indy 10 SVN revision, a new hoNoProtocolErrorException flag was recently added to the TIdHTTP.HTTPOptions property so the EIdHTTPProtocolException exception is not raised for any response code.
Successful resposes are 2xx List_of_HTTP_status_codes
i did the following. Process straight all 200`s and LOG exceptions. worked, not a single non 200 - except unauthorized and timeouts (password or sometimes unavaliable server). but many/all responses will be considered for a wide range of mainstream apps.
while (iRedo < 3) do begin
s := Self.HTTPComponent.Get( sUrl );
if self.HTTPComponent.ResponseCode = 200 then begin
break;
end;
// IDEIA - log what happend if not 200
logWhatHappend( s, HTTPComponent ); // then log content, headers, etc
inc( iRedo ); sleep( 5 );
end;
How do I invoke a Service Operation in WCF from iOS?
I have a Service Operation defined in my WCF Data Service (tied to a stored procedure in my DB schema) that I need to invoke from iOS. Say I've got the following declaration in my .svc.cs file:
[WebInvoke(RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.WrappedRequest)]
public IQueryable<Foo> GetFoos(int param1, DateTime param2, string param3)
{
return CurrentDataSource.GetFoos(param1, param2, param3).AsQueryable();
}
And I've got it set up with the proper rights in InitializeService:
config.SetServiceOperationAccessRule("GetFoos", ServiceOperationRights.AllRead);
When I try to invoke this via HTTP POST from iOS, I get back an error wrapped in JSON:
Bad Request - Error in query syntax.
It seems like it doesn't like how I'm passing my parameters. I'm passing them JSON-encoded (using NSJSONSerialization to turn an NSDictionary into a JSON string) in the request body of a POST request. The same method works on another web service (.svc) not connected to WCF that has operations annotated the same way.
An answer to another question of mine in a similar vein suggests that data formats can be negotiated between client and server, and I've read that dates are a pain to format, so maybe it's my DateTime parameter that's a problem. But I've tried both the JSON format (\/Date(836438400000)\/ and /Date(836438400000)/) and the JSON Light format (1996-07-16T00:00:00) to no avail.
So my question is this: what is the proper way to invoke this operation? If I need to have my app tell the server what format to expect, how do I do that?
Update: I tried using the format datetime'1996-07-16T00:00:00' as mentioned in this question. Same error.
Update 2: The MSDN page for Service Operations seems to suggest that nothing besides Method = "POST" is supported when annotating the WebInvoke for a Service Operation. I tried removing everything from what is quoted in the above code and setting the method to POST. Same error.
Update 3: On Pawel's suggestion, I made a new Service Operation on my Data Service just like this:
[WebInvoke(Method = "POST")]
public IQueryable<string> GetFoos()
{
List<string> foos = new List<string>();
foos.Add("bar");
return foos.AsQueryable();
}
I was able to make it work in Fiddler's Composer pane by setting the method to POST, adding accept:application/json;charset=utf-8 and Content-Length:0 to the headers. Then I added a single int parameter to the operation (called param1). I set the body of my request in Fiddler to {"param1":"1"} and ran it (and Fiddler automatically updated my content-length header), and got the same error. I changed the type of my parameter to string and ran my request again and it worked. So my problem seems to be non-string types.
You need to send parameters in the Url and not in the request body.