Http request using "POST" method can't pass parameter

[yexioamu]

[ FlexSim 21.2.4 ]

Hi, I have a question about Http Request. When I want to request data from a remote server, the interface of the server only can be requested by "POST" method. I used two functions that I can find in this forum website.

One is applicationcommand("sendhttprequest", verb, server, object, data, silent, result), the value of verb is "POST", server is the IP of the remote server, object is the path of the interface, when I run the model, I can see the call record of the interface in the remote server, but it reports "The passed parameters is empty", It seems like the data is not passed.

string verb = "POST";
//this is the name or IP address of the server the request will be sent to
string server =  "xx.xxx.xxx.xxx"; //it is the IP of the remote server
//object represents the rest of the URL after the server name
string data ="?&reqCode=123";
string object =  "/services/genAgvTask";
//silent is a flag indicating whether you want any errors to be printed to FlexSim's system console (Debug > System Console)
int silent = 1;
//specify a text node in the tree where the server's response will be written
treenode result = node("/Tools/result", model());
//send the HTTP request
applicationcommand("sendhttprequest", verb, server, object, data, silent, result

Another is Http.Request, my code like this,

Http.Request request = Http.Request("IP/services/genAgvTask");
request.method = Http.Method.Post;
request.data = "reqCode=123";
request.useSSL = 0;
Http.Response response = request.sendAndWait();
string json = response.value;
Map map = JSON.parse(json

But it still can't work, the remote server still reports "The passed parameters is empty".

And then, I searched the docs(Post Method), it show that the description of the "Post" method is "Method to create or replace a target resource with specified data", can this method request data from server?

I'm so confused about this question a few weeks, can you give me some suggestions, and offer a example about request data by using "POST" method.

Thank you very much!

Yexioamu

[yexioamu]

@Ben Wilson@Phil BoBo Dear Mr. Wilson and Mr.BoBo, I have read several questions that answered from you, But most of them is the "GET" method, so i still can't got the correct use method. Can you pay attention to this issue when you are free？Thank you very much!

[Ben_WilsonADSK · Accepted solution]

Both methods look like they work fine. I just used httpbin.org, which mirrors back to you whatever you send it. I tested against their POST endpoint at httpbin.org/post.

Here are the results using Http.Request

And using application command sendhttprequest

My sample model file is attached.

http_post_test_v21.2.fsm

[yexioamu]

I tried your sample model, it work well, but my model is still not work, Maybe it is the problem of the remote server interface，I will check it with my R&D colleagues，Mr. Wilson, I owe you my best thanks！ I will reply you the follow-up results here in the next few days.

[yexioamu]

Hi, Mr.Wilson, i check it with my colleagues, Maybe the problem is my remote server requires header is 'application/json', but the header of this two method in flexsim(version 21.2.4) is 'application/x-www-form-urlencoded', I read your comments on this question(Sending Http.request for json content type), but i can't understand the custom labelProperties property ，can it solve my problem? or any other solution?

[Ben_WilsonADSK]

@yexioamu, FlexSim version 22.1.0 added the ability to set custom request headers for Http.Request (documentation, release notes).

In the attached example you can see the request.headers setter, where I specify JSON, and in the response that header is mirrored back.

You would need to upgrade your FlexSim version to version 22.1 or higher take advantage of this new feature.

http_post_test_v22.1.fsm

[yexioamu]

Thank for your answer, i tried the request.headers you suggested in the version 23.05 by using PF, it works well! But due to my company software purchase policy, i can't upgrade my FlexSim version quickly, does it possible that achieve it in version 21.2.4, or can i achieve it by using DLL function? If it is possible, can i get some references from anywhere?

[philboboADSK]

Yes, if you want to use C++, you can use the 21.2 Module SDK or the FlexSim DLL Maker (in the 'Modules' section of https://account.flexsim.com/downloads/).

For an example of sending HTTP requests, see: https://learn.microsoft.com/en-us/windows/win32/winhttp/winhttp-sessions-overview

[yexioamu]

Thanks for your answer! i will try it. thanks again!

[yexioamu]

Hi, BoBo, i am tring the dll maker, i use the winhttp method you suggested in a pure cpp project at first, and it work well.

Then, i create a function named HttpRequest in the mydll.cpp of the dllmaker, and then use const char* variables to put the parameters from flexsim user command, but it seems like the order of the parstr is disordered, and some parameters is repeated, i am confused about it.

and then, i use string to put the parameters from flexsim and transform to wchar_t* so that the winhttp method can accept, but it just display the first letter of the value, and iti is also work well in the pure cpp project. i am confused about it too.

My code in flexsim is next, command2 is a user command.

string server =  "xx.xx.xx.xx";

string verb = "POST";

string path =  "/services/genAgvTask";

string headers = "Content-Type: application/json";

string data ="{\"reqCode\":\"123\"}";

command2(server, verb, path, headers, data);

Could you help me? Thank you!

attachment.zip

[philboboADSK]

The FlexSim Support answer to your question is to simply use the latest FlexSim version. We've already solved this issue.

If you want detailed help in resolving this in an older version, contact your local distributor for direct support. @CSN

[yexioamu]

What a pity for me，whatever，I am appreciated for your answers，thanks again