在Delphi中使用TIdHTTP通过用户身份验证模拟curl命令

问题描述

我正在尝试在Delphi中使用TIdHTTP来模拟以下卷曲操作：

curl -X POST -F "message={\"user_email\" : \"useremail@domain.com\",\"user_password\" : \"UserPassword\"}" "https://esm-db.eu/esmws/generate-signed-message/1/query" > token.txt

服务器端的准则在：https://esm-db.eu/esmws/generate-signed-message/1/query-options.html

中给出

成功的curl连接的详细输出如下：

Note: Unnecessary use of -X or --request,POST is already inferred.
*   Trying 193.206.88.90...
* TCP_NODELAY set
* Connected to esm-db.eu (193.206.88.90) port 443 (#0)
* schannel: SSL/TLS connection with esm-db.eu port 443 (step 1/3)
* schannel: checking server certificate revocation
* schannel: sending initial handshake data: sending 174 bytes...
* schannel: sent initial handshake data: sent 174 bytes
* schannel: SSL/TLS connection with esm-db.eu port 443 (step 2/3)
* schannel: Failed to receive handshake,need more data
* schannel: SSL/TLS connection with esm-db.eu port 443 (step 2/3)
* schannel: encrypted data got 2954
* schannel: encrypted data buffer: offset 2954 length 4096
* schannel: sending next handshake data: sending 93 bytes...
* schannel: SSL/TLS connection with esm-db.eu port 443 (step 2/3)
* schannel: encrypted data got 258
* schannel: encrypted data buffer: offset 258 length 4096
* schannel: SSL/TLS handshake complete
* schannel: SSL/TLS connection with esm-db.eu port 443 (step 3/3)
* schannel: stored credential handle in session cache
> POST /esmws/generate-signed-message/1/query HTTP/1.1
> Host: esm-db.eu
> User-Agent: curl/7.55.1
> Accept: */*
> Content-Length: 217
> Expect: 100-continue
> Content-Type: multipart/form-data; boundary=------------------------7682f54661679429
>
* schannel: client wants to read 102400 bytes
* schannel: encdata_buffer resized 103424
* schannel: encrypted data buffer: offset 0 length 103424
* schannel: encrypted data got 54
* schannel: encrypted data buffer: offset 54 length 103424
* schannel: decrypted data length: 25
* schannel: decrypted data added: 25
* schannel: decrypted data cached: offset 25 length 102400
* schannel: encrypted data buffer: offset 0 length 103424
* schannel: decrypted data buffer: offset 25 length 102400
* schannel: schannel_recv cleanup
* schannel: decrypted data returned 25
* schannel: decrypted data buffer: offset 0 length 102400
< HTTP/1.1 100 Continue
* schannel: client wants to read 102400 bytes
* schannel: encrypted data buffer: offset 0 length 103424
* schannel: encrypted data got 924
* schannel: encrypted data buffer: offset 924 length 103424
* schannel: decrypted data length: 895
* schannel: decrypted data added: 895
* schannel: decrypted data cached: offset 895 length 102400
* schannel: encrypted data buffer: offset 0 length 103424
* schannel: decrypted data buffer: offset 895 length 102400
* schannel: schannel_recv cleanup
* schannel: decrypted data returned 895
* schannel: decrypted data buffer: offset 0 length 102400
< HTTP/1.1 200 OK
< Server: Nginx/1.10.3
< Date: Sun,08 Nov 2020 23:20:51 GMT
< Content-Type: text/plain; charset=UTF-8
< Content-Length: 649
< Connection: keep-alive
< Access-Control-Allow-Origin: *
< Access-Control-Allow-Methods: POST,GET,OPTIONS
<
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

但是，在TIdHTTP下，我不断收到HTTP/1.1 400 Bad Request错误。我在做什么错了？

procedure TMainForm.HTTPGetTokenFile;
var
  IdHTTP: TIdHTTP;
  Params: TIdMultipartFormDataStream;
  LHandler: TIdSSLIOHandlerSocketopenSSL;
begin
  try
    Params := TIdMultipartFormDataStream.Create;
    Params.AddFormField('message','{\"user_email\" : \"useremail@domain.com\",\"user_password\" : \"UserPassword\"}');
    try
      IdHTTP := TIdHTTP.Create(nil);
      try
        LHandler := TIdSSLIOHandlerSocketopenSSL.Create(IdHTTP);
        LHandler.SSLOptions.Method := sslvTLSv1;
        IdHTTP.IOHandler := LHandler;
        IdHTTP.Request.Accept := 'application/json,text/plain;q=0.9,text/html;q=0.8';
        IdHTTP.Request.ContentType := 'application/json';
        Memo1.Text := IdHTTP.Post('https://esm-db.eu/esmws/generate-signed-message/1/query',Params);
      finally
        IdHTTP.Free;
      end;
    finally
      Params.Free;
    end;
  except
    on E: Exception do
      ShowMessage('Error: ' + E.ToString);
  end;
end;

更新：我删除了JSON中的\个字符，但仍然出现HTTP/1.1 400 Bad Request错误。

procedure TMainForm.HTTPGetTokenFile;
var
  IdHTTP: TIdHTTP;
  Params: TIdMultipartFormDataStream;
  LHandler: TIdSSLIOHandlerSocketopenSSL;
begin
  try
    Params := TIdMultipartFormDataStream.Create;
    Params.AddFormField('message','{"user_email" : "useremail@domain.com","user_password" : "UserPassword"}');
    try
      IdHTTP := TIdHTTP.Create(nil);
      try
        LHandler := TIdSSLIOHandlerSocketopenSSL.Create(IdHTTP);
        LHandler.SSLOptions.Method := sslvTLSv1;
        IdHTTP.IOHandler := LHandler;
        IdHTTP.Request.Accept := 'application/json,Params);
      finally
        IdHTTP.Free;
      end;
    finally
      Params.Free;
    end;
  except
    on E: Exception do
      ShowMessage('Error: ' + E.ToString);
  end;
end;

来自TIdHTTP的转储如下：

Stat Connected.
Sent 9/11/2020 4:36:55 ??: POST /esmws/generate-signed-message/1/query HTTP/1.0<EOL>Content-Type: multipart/form-data; boundary=--------110920163653921<EOL>Content-Length: 257<EOL>Host: esm-db.eu<EOL>Accept: application/json,text/html;q=0.8<EOL>Accept-Encoding: identity<EOL>User-Agent: Mozilla/3.0 (compatible; Indy Library)<EOL><EOL>
Sent 9/11/2020 4:36:55 ??: ----------110920163653921<EOL>Content-disposition: form-data; name="message"<EOL>Content-Type: text/plain<EOL>Content-transfer-encoding: quoted-printable<EOL><EOL>{"user_email" : "s.antonIoU@seismosoft.com","user_password" : "passw=<EOL>ord"}<EOL>----------110920163653921--<EOL>
Recv 9/11/2020 4:36:55 ??: HTTP/1.1 400 Bad Request<EOL>Server: Nginx/1.10.3<EOL>Date: Mon,09 Nov 2020 14:36:56 GMT<EOL>Content-Type: text/html; charset=UTF-8<EOL>Content-Length: 121<EOL>Connection: close<EOL>Access-Control-Allow-Origin: *<EOL>Access-Control-Allow-Methods: POST,OPTIONS<EOL><EOL>{"http_code": 400,"http_label": "Bad Request","exit_message": "ERROR: improper specification / unrecognized parameter"}
Stat disconnected.
Stat disconnected.
Stat disconnected.

似乎AddFormField()函数的争论限制为70个字符，最后3个字符似乎已被切断。我可以增加此限制，还是应该减小传递的值的大小（例如，删除不必要的空格）？

解决方法

如Dave在评论中所述，您需要删除JSON数据中的\字符。 Delphi不会像命令行处理器那样转义字符。 "在Delphi中不是保留字符，因此不需要在Delphi字符串文字中转义"字符。

另一方面，在这种情况下，IdHTTP.Request.ContentType的分配是多余的，应将其删除。 Post()使用TIdMultiPartFormDataStream会用自己的值覆盖ContentType，而忽略您分配的任何内容。

尝试以下方法：

procedure TMainForm.HTTPGetTokenFile;
var
  IdHTTP: TIdHTTP;
  Params: TIdMultipartFormDataStream;
  LHandler: TIdSSLIOHandlerSocketOpenSSL;
begin
  try
    Params := TIdMultipartFormDataStream.Create;
    try
      Params.AddFormField('message','{"user_email" : "useremail@domain.com","user_password" : "UserPassword"}');

      IdHTTP := TIdHTTP.Create(nil);
      try
        LHandler := TIdSSLIOHandlerSocketOpenSSL.Create(IdHTTP);
        LHandler.SSLOptions.Method := sslvTLSv1;
        IdHTTP.IOHandler := LHandler;
        IdHTTP.Request.Accept := 'application/json,text/plain;q=0.9,text/html;q=0.8';
        Memo1.Text := IdHTTP.Post('https://esm-db.eu/esmws/generate-signed-message/1/query',Params);
      finally
        IdHTTP.Free;
      end;
    finally
      Params.Free;
    end;
  except
    on E: Exception do
      ShowMessage('Error: ' + E.ToString);
  end;
end;

更新：事实证明，TIdMultiPartFormDataStream以Quoted-Printable格式发送JSON，每70个JSON中间插入一个“软”换行符字符。显然，您的服务器不正确支持该编码。默认情况下，curl不会使用Quoted-Printable进行Web表单提交，除非您明确要求这样做。

您可以通过以下任一方式禁用Quoted-Printable中的TIdMultipartFormDataStream编码：

将TIdFormDataField.ContentTransfer属性设置为'7bit'，'8bit'，'binary'或''（实际上与'7bit'相同，无需通过Content-Transfer-Encoding标头显式通知服务器），例如：

procedure TMainForm.HTTPGetTokenFile;
var
  IdHTTP: TIdHTTP;
  Params: TIdMultipartFormDataStream;
  LHandler: TIdSSLIOHandlerSocketOpenSSL;
begin
  try
    Params := TIdMultipartFormDataStream.Create;
    try
      with Params.AddFormField('message',"user_password" : "UserPassword"}') do
      begin
        Charset := 'utf-8';
        ContentTransfer := '8bit';
      end;

      IdHTTP := TIdHTTP.Create(nil);
      try
        LHandler := TIdSSLIOHandlerSocketOpenSSL.Create(IdHTTP);
        LHandler.SSLOptions.Method := sslvTLSv1;
        IdHTTP.IOHandler := LHandler;
        IdHTTP.Request.Accept := 'application/json,Params);
      finally
        IdHTTP.Free;
      end;
    finally
      Params.Free;
    end;
  except
    on E: Exception do
      ShowMessage('Error: ' + E.ToString);
  end;
end;

使用AddFormField()而不是TStream的{{1}}重载。您可以将JSON放入String中，例如：

TStringStream

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