Delphi & Indy httpServer 如何停止发送 400 错误请求

Question

我从期望他返回 ACK (HTTP1/1 200 OK) 的设备获取数据。我的 httpserver 在收到 header 后自动 returned 400 Bad Request（我在 WareShark 上看到）。也许设备没有按照他的要求正确构建。我如何停止服务器不return一个错误？所以我将能够继续与设备通信。

谢谢

LOG: 192.168.1.141:57565 Stat Connected.

HTTP Connect 192.168.1.141
LOG: 192.168.1.141:57565 Recv 10.4.2017 г. 00:18:43: POST / HTTP/1.1<EOL>

LOG: 192.168.1.141:57565 Recv 10.4.2017 г. 00:18:43: Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-excel, application/msword, application/x-shockwave-flash, text/*, */*<EOL>Accept-Language: en-us<EOL>Content-Type: application/x-www-form-urlencoded<EOL>Accept-Encoding: gzip, deflate<EOL>User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.0.3705)<EOL>Content-Length: 579<EOL>Connection: Keep-Alive<EOL><EOL><?xml version="1.0"?><EOL><Metrics  SiteId="BG-001" Sitename="office Pazardjik"><EOL><Properties><EOL><MacAddress>00:b0:9d:7f:b7:b2</MacAddress><EOL><IpAddress>0.0.0.0</IpAddress><EOL><Timezone>2</Timezone><EOL><DST>1</DST><EOL><DeviceType>0</DeviceType><EOL><SerialNumber>8370098</SerialNumber><EOL></Properties><EOL><ReportData  Interval="1"><EOL><Report  Date="2017-04-06"><EOL><Object  Id="0" DeviceId="BG-001-01" Devicename="Main Entrance" ObjectType="0" Name="Main Entrance"><EOL><Count  StartTime="05:31:00" EndTime="05:32:00" Enters="0" Exits="0" Status="0"/><EOL></Object><EOL></Report><EOL></ReportData><EOL></Metrics><EOL>

HTTP Header 
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-excel, application/msword, application/x-shockwave-flash, text/*, */*
Accept-Language: en-us
Content-Type: application/x-www-form-urlencoded
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.0.3705)
Content-Length: 579
Connection: Keep-Alive

LOG: 192.168.1.141:57565 Sent 10.4.2017 г. 00:18:43: HTTP/1.1 400 Bad Request<EOL>Connection: close<EOL>Content-Length: 0<EOL>Date: Sun, 09 Apr 2017 21:18:43 GMT<EOL><EOL>


LOG: 192.168.1.141:57565 Stat Disconnected.
LOG: 0.0.0.0:0 Stat Disconnected.

Answer 1

HTTP 客户端正在发送 HTTP 1.1 请求，但未发送必需的 Host 请求 header。每 RFC 2616 Section 14.23:

A client MUST include a Host header field in all HTTP/1.1 request messages. If the requested URI does not include an Internet host name for the service being requested, then the Host header field MUST be given with an empty value. An HTTP/1.1 proxy MUST ensure that any request message it forwards does contain an appropriate Host header field that identifies the service being requested by the proxy. All Internet-based HTTP/1.1 servers MUST respond with a 400 (Bad Request) status code to any HTTP/1.1 request message which lacks a Host header field.

TIdHTTPServer returns 如果收到没有 Host header 的 HTTP 1.1 请求，则返回 400 响应。正如您在上面看到的，400 响应是 HTTP 1.1 规范强制要求的。我建议您联系设备制造商并报告有关丢失 Host header 的错误，也许他们可以发布固件更新。

同时，您可以使用 TIdHTTPServer.OnHeadersAvailable 事件插入一个虚拟 Host header 如果它丢失：

procedure httpServerHeadersAvailable(AContext: TIdContext; const AUri: string; AHeaders: TIdHeaderList; var VContinueProcessing: Boolean);
begin
  if AHeaders.Values['Host'] = '' then
    AHeaders.Values['Host'] = 'myserver';
  VContinueProcessing := true;
end;

至于您的日志，它显示在您的 OnCommandGet 事件处理程序中发生访问冲突，原因是访问了一个 nil 指针。在客户端 Host header 丢失的情况下，不会触发该事件。所以你的代码中显然有第二个问题，与这个问题无关。

Delphi & Indy httpServer 如何停止发送 400 错误请求

Delphi & Indy httpServer how stop sending 400 bad Request

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