How to call WebApi in Delphi
How to call WebApi in Delphi? for this problem, this article introduces the corresponding analysis and solution in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible way.
When Delphi calls WebApi, we use IXMLHttpRequest. Just add msxml to the unit reference.
It is very simple to call, defining HttpReq: IXMLHttpRequest
HttpReq: = CoXMLHTTPRequest.Create
HttpReq.open ('Post', url, False, EmptyParam, EmptyParam)
The first of the above parameters is the method used, GET writes' Get',Post, write 'Post', the second is the mailing address, and the latter is filled in by default.
HttpReq.setRequestHeader ('Accept',' application/json')
HttpReq.setRequestHeader ('Content-Type',' application/json')
Above is the format of the request header
HttpReq.send (parasjson); / / start search
In Send, if you use the GET method, fill in the EmptyParam directly. If you use the POST method, fill in your own JSON string here.
Resultjson: = HttpReq.responseText
Get the return information
The GET method must pay attention to one thing.
Delphi must add a timestamp'& timestamp='+inttostr (Windows.GetTickCount) when using IXMLHttpRequest's GET method. If there is no timestamp after that, it will only GET once and no longer request GET.
Self-encapsulated complete unit that calls WebApi
Unit DoWebApi
Interface
Uses
Variants, msxml, SysUtils, Windows
/ / WebApi
/ / GET
Function WebApiGet (url: string; var resultjson: string; parasstr:string=''): Integer
/ / Post
Function WebApiPost (url, parasjson: string; var resultjson: string): Integer
Implementation
/ / obtain Get
/ / delphi must be timestamped'& timestamp='+inttostr (Windows.GetTickCount) when using IXMLHttpRequest's GET method.
/ / if you don't add it, you will only GET once, and you will no longer GET.
/ / Added by Administrator 2016-09-23 16:17:08
Function WebApiGet (url: string; var resultjson: string;parasstr:string=''): Integer
Var
Transurl: string
HttpReq: IXMLHttpRequest
Begin
If parasstr =''then
Transurl: = url +'? timestamp=' + inttostr (Windows.GetTickCount)
Else
Transurl: = url +'?'+ parasstr +'& timestamp=' + inttostr (Windows.GetTickCount)
Result: =-1
Try
Try
HttpReq: = CoXMLHTTPRequest.Create
HttpReq.open ('get', transurl, False, EmptyParam, EmptyParam)
HttpReq.setRequestHeader ('Accept',' application/json')
HttpReq.setRequestHeader ('Content-Type',' application/json')
HttpReq.send (EmptyParam); / / start search
Resultjson: = HttpReq.responseText
Result: = 0
Except
Result: =-1
End
Finally
End
End
/ / Post
Function WebApiPost (url, parasjson: string; var resultjson: string): Integer
Var
HttpReq: IXMLHttpRequest
Begin
Result: =-1
Try
HttpReq: = CoXMLHTTPRequest.Create
HttpReq.open ('Post', url, False, EmptyParam, EmptyParam)
HttpReq.setRequestHeader ('Accept',' application/json')
HttpReq.setRequestHeader ('Content-Type',' application/json')
HttpReq.send (parasjson); / / start search
Resultjson: = HttpReq.responseText
Result: = 0
Except
Result: =-1
End
End
End.
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