--- a/Core/HttpServer/HttpOutput.cpp	Sun Jan 20 14:02:49 2019 +0100
+++ b/Core/HttpServer/HttpOutput.cpp	Mon Jan 21 12:09:04 2019 +0100
@@ -407,12 +407,6 @@
       throw OrthancException(ErrorCode_ParameterOutOfRange);
     }
 
-    if (keepAlive_)
-    {
-      throw OrthancException(ErrorCode_NotImplemented,
-                             "Multipart answers are not implemented together with keep-alive connections");
-    }
-
     if (state_ != State_WritingHeader)
     {
       throw OrthancException(ErrorCode_BadSequenceOfCalls);
@@ -428,6 +422,20 @@
 
     std::string header = "HTTP/1.1 200 OK\r\n";
 
+    if (keepAlive_)
+    {
+#if ORTHANC_ENABLE_MONGOOSE == 1
+      throw OrthancException(ErrorCode_NotImplemented,
+                             "Multipart answers are not implemented together "
+                             "with keep-alive connections if using Mongoose");
+#else
+      // Turn off Keep-Alive for multipart answers
+      // https://github.com/civetweb/civetweb/issues/727
+      stream_.DisableKeepAlive();
+      header += "Connection: close\r\n";
+#endif
+    }
+
     // Possibly add the cookies
     for (std::list<std::string>::const_iterator
            it = headers_.begin(); it != headers_.end(); ++it)

--- a/Core/HttpServer/HttpServer.cpp	Sun Jan 20 14:02:49 2019 +0100
+++ b/Core/HttpServer/HttpServer.cpp	Mon Jan 21 12:09:04 2019 +0100
@@ -108,6 +108,16 @@
       {
         // Ignore this
       }
+
+      virtual void DisableKeepAlive()
+      {
+#if ORTHANC_ENABLE_MONGOOSE == 1
+        throw OrthancException(ErrorCode_NotImplemented,
+                               "Only available if using CivetWeb");
+#elif ORTHANC_ENABLE_CIVETWEB == 1
+        mg_disable_keep_alive(connection_);
+#endif
+      }
     };
 
 

--- a/Core/HttpServer/IHttpOutputStream.h	Sun Jan 20 14:02:49 2019 +0100
+++ b/Core/HttpServer/IHttpOutputStream.h	Mon Jan 21 12:09:04 2019 +0100
@@ -50,5 +50,9 @@
     virtual void OnHttpStatusReceived(HttpStatus status) = 0;
 
     virtual void Send(bool isHeader, const void* buffer, size_t length) = 0;
+
+    // Disable HTTP keep alive for this single HTTP connection. Must
+    // be called before sending the "HTTP/1.1 200 OK" header.
+    virtual void DisableKeepAlive() = 0;
   };
 }

--- a/Core/HttpServer/StringHttpOutput.h	Sun Jan 20 14:02:49 2019 +0100
+++ b/Core/HttpServer/StringHttpOutput.h	Mon Jan 21 12:09:04 2019 +0100
@@ -54,6 +54,10 @@
 
     virtual void Send(bool isHeader, const void* buffer, size_t length);
 
+    virtual void DisableKeepAlive()
+    {
+    }
+
     void GetOutput(std::string& output);
   };
 }

--- a/NEWS	Sun Jan 20 14:02:49 2019 +0100
+++ b/NEWS	Mon Jan 21 12:09:04 2019 +0100
@@ -1,6 +1,7 @@
 Pending changes in the mainline
 ===============================
 
+* Fix compatibility with DICOMweb plugin (allow multipart answers over HTTP Keep-Alive)
 
 
 Version 1.5.2 (2019-01-18)

--- a/Resources/Patches/civetweb-1.11.patch	Sun Jan 20 14:02:49 2019 +0100
+++ b/Resources/Patches/civetweb-1.11.patch	Mon Jan 21 12:09:04 2019 +0100
@@ -1,6 +1,20 @@
+diff -urEb civetweb-1.11.orig/include/civetweb.h civetweb-1.11/include/civetweb.h
+--- civetweb-1.11.orig/include/civetweb.h	2019-01-17 21:09:41.844888908 +0100
++++ civetweb-1.11/include/civetweb.h	2019-01-21 12:05:08.138998659 +0100
+@@ -1507,6 +1507,10 @@
+ #endif
+ 
+ 
++// Added by SJ
++CIVETWEB_API void mg_disable_keep_alive(struct mg_connection *conn);
++
++
+ #ifdef __cplusplus
+ }
+ #endif /* __cplusplus */
 diff -urEb civetweb-1.11.orig/src/civetweb.c civetweb-1.11/src/civetweb.c
 --- civetweb-1.11.orig/src/civetweb.c	2019-01-17 21:09:41.852888857 +0100
-+++ civetweb-1.11/src/civetweb.c	2019-01-17 21:23:54.273424124 +0100
++++ civetweb-1.11/src/civetweb.c	2019-01-21 12:06:35.826868284 +0100
 @@ -59,6 +59,9 @@
  #if defined(__linux__) && !defined(_XOPEN_SOURCE)
  #define _XOPEN_SOURCE 600 /* For flockfile() on Linux */
@@ -68,3 +82,17 @@
  	conn->host = alloc_get_host(conn);
  	if (!conn->host) {
  		mg_snprintf(conn,
+@@ -19857,4 +19882,13 @@
+ }
+ 
+ 
++// Added by SJ
++void mg_disable_keep_alive(struct mg_connection *conn)
++{
++  if (conn != NULL) {
++    conn->must_close = 1;
++  }
++}
++
++
+ /* End of civetweb.c */