问题
I have encountered a few sites that uses JSON
for request and response
I come across two types :
1- application/x-www-form-urlencoded
as request and return a response application/json
content type
2- application/json
content type for both request and response
in type 1
i tried changing the the response content type usingmIdHttp.Response.ContentType := 'application/json';
but using http analyzer i can see that it doesn't change and its still text/html
now i do not know if the problem is with the fact that i can't change content type or not but i do not know how to deal with json
!
a few question regarding json
:
1- do i have to encode json data when posting ? how ?
2- how can i parse the json response code ? how to get it ? does it need some kind of encode or special convertion ?
3- what kind of idhttp setting for json changes with each site and needs configuring ?
I understand my questions sound a bit general, but all the other questions are very specific and don't explain the basics when dealing with 'application/json'
content type.
Edit 1 :
thanks to Remy Lebeau answer i was able to successfully work with type 1
but i still have trouble sending JSON
request, can someone please share an working example, this is one of the sites posting information please use this for your example :
One important note : this particular site's post and request content are exactly like each other ! and it baffles me because at the site, i specify an start date
and an end date
then click on a folder like icon
and this post
is sent (the one you can see above), and the result
should be links
(and it is) but instead of appearing only in request content
they also appear in post
! (also i'm trying to get the links but at the post
the links, the thing i want, are also being sent, how can i post something i don't have !!?)
just for more clarity here is the place i fill the date and the icon i mentioned :
回答1:
You cannot specify the format of the response, unless the requested resource offers an explicit input parameter or dedicated URL for that exact purpose (ie, to request a response be sent as html, xml, json, etc). Setting the TIdHTTP.Response.ContentType
property is useless. It will be overwritten by the actual Content-Type
header of the response.
To send JSON in a request, you must post it as a TStream
, like TMemoryStream
or TStringStream
, and set the TIdHTTP.Request.ContentType
as needed, eg:
var
ReqJson: TStringStream;
begin
ReqJson := TStringStream.Create('json content here', TEncoding.UTF8);
try
IdHTTP1.Request.ContentType := 'application/json';
IdHTTP1.Post(URL, ReqJson);
finally
ReqJson.Free;
end;
end;
To receive JSON, TIdHTTP
can either
return it as a
String
(decoded using a server-reported charset):var ReqJson: TStringStream; RespJson: String; begin ReqJson := TStringStream.Create('json content here', TEncoding.UTF8); try IdHTTP1.Request.ContentType := 'application/json'; RespJson := IdHTTP1.Post(URL, ReqJson); finally ReqJson.Free; end; // use RespJson as needed... end;
write the raw bytes to an output
TStream
of your choosing:var ReqJson: TStringStream; RespJson: TMemoryStream; begin RespJson := TMemoryStream.Create; try ReqJson := TStringStream.Create('json content here', TEncoding.UTF8); try IdHTTP1.Request.ContentType := 'application/json'; RespJson := IdHTTP1.Post(URL, ReqJson, RespJson); finally ReqJson.Free; end; RespJson.Position := 0; // use RespJson as needed... finally RespJson.Free; end; end;
The HTTP response code is available in the TIdHTTP.Response.ResponseCode
(and TIdHTTP.ResponseCode
) property.
来源:https://stackoverflow.com/questions/39056821/idhttp-how-to-deal-with-json-request-and-response