I parse/scrape a few web page every now and then and recently ran across an error that stated:
"The server committed a protocol violation. Section=ResponseStatusLine".
Cause?:
On this page, I found an answer that suggests simply that the server header does not conform to the HTTP v1.1 specification.
[Paraphrased...]
This issue is caused when a response followed by a request to {certain} services violate the HTTP v1.1 specification.
As an example, HTTP header keys should specifically not include any spaces in their names.
Some web servers do not fully respect this which causes this error to occur.
The Microsoft .Net framework enforces the HTTP v1.1 specification and will reject any responses that do not adhere to the specification.
When a validation failure occurs then a protocol violation error is generated.
To resolve this issue any gateway/proxy level network components should been upgraded or corrected to properly adhere to the HTTP v1.1 specification.
After a few web searches, I found a couple of suggestions – one of which said the problem could be fixed by changing the HttpWebRequest ProtocolVersion to 1.0 with the command:
1: HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(strURI);
2: req.ProtocolVersion = HttpVersion.Version10;
…but that did not work in my particular case.
What DID work was the next suggestion I found that suggested the use of the setting: “useUnsafeHeaderParsing” either in the app.config file or programmatically.
If added to the app.config, it would be:
1: <!-- after the applicationSettings -->
2: <system.net>
3: <settings>
4: <httpWebRequest useUnsafeHeaderParsing ="true"/>
5: </settings>
6: </system.net>
If done programmatically, it would look like this:
C++:
1: // UUHP_CPP.h
2: #pragma once
3: using namespace System;
4: using namespace System::Reflection;
5:
6: namespace UUHP_CPP
7: {
8: public ref class CUUHP_CPP
9: {
10: public:
11: static bool UseUnsafeHeaderParsing(String^% strError)
12: {
13: Assembly^ assembly = Assembly::GetAssembly(System::Net::Configuration::SettingsSection::typeid); //__typeof
14: if (nullptr==assembly)
15: {
16: strError = "Could not access Assembly";
17: return false;
18: }
19:
20: Type^ type = assembly->GetType("System.Net.Configuration.SettingsSectionInternal");
21: if (nullptr==type)
22: {
23: strError = "Could not access internal settings";
24: return false;
25: }
26:
27: Object^ obj = type->InvokeMember("Section",
28: BindingFlags::Static | BindingFlags::GetProperty | BindingFlags::NonPublic,
29: nullptr, nullptr, gcnew array<Object^,1>(0));
30:
31: if(nullptr == obj)
32: {
33: strError = "Could not invoke Section member";
34: return false;
35: }
36:
37: FieldInfo^ fi = type->GetField("useUnsafeHeaderParsing", BindingFlags::NonPublic | BindingFlags::Instance);
38: if(nullptr == fi)
39: {
40: strError = "Could not access useUnsafeHeaderParsing field";
41: return false;
42: }
43:
44: if (!(bool)fi->GetValue(obj))
45: {
46: fi->SetValue(obj, true);
47: }
48:
49: return true;
50: }
51: };
52: }
C# (CSharp):
1: using System;
2: using System.Reflection;
3:
4: namespace UUHP_CS
5: {
6: public class CUUHP_CS
7: {
8: public static bool UseUnsafeHeaderParsing(ref string strError)
9: {
10: Assembly assembly = Assembly.GetAssembly(typeof(System.Net.Configuration.SettingsSection));
11: if (null == assembly)
12: {
13: strError = "Could not access Assembly";
14: return false;
15: }
16:
17: Type type = assembly.GetType("System.Net.Configuration.SettingsSectionInternal");
18: if (null == type)
19: {
20: strError = "Could not access internal settings";
21: return false;
22: }
23:
24: object obj = type.InvokeMember("Section",
25: BindingFlags.Static | BindingFlags.GetProperty | BindingFlags.NonPublic,
26: null, null, new object[] { });
27:
28: if (null == obj)
29: {
30: strError = "Could not invoke Section member";
31: return false;
32: }
33:
34: // If it's not already set, set it.
35: FieldInfo fi = type.GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic | BindingFlags.Instance);
36: if (null == fi)
37: {
38: strError = "Could not access useUnsafeHeaderParsing field";
39: return false;
40: }
41:
42: if (!Convert.ToBoolean(fi.GetValue(obj)))
43: {
44: fi.SetValue(obj, true);
45: }
46:
47: return true;
48: }
49: }
50: }
F# (FSharp):
1: namespace UUHP_FS
2: open System
3: open System.Reflection
4: module CUUHP_FS =
5: let UseUnsafeHeaderParsing(strError : byref<string>) : bool =
6: //
7: let assembly : Assembly = Assembly.GetAssembly(typeof<System.Net.Configuration.SettingsSection>)
8: if (null = assembly) then
9: strError <- "Could not access Assembly"
10: false
11: else
12:
13: let myType : Type = assembly.GetType("System.Net.Configuration.SettingsSectionInternal")
14: if (null = myType) then
15: strError <- "Could not access internal settings"
16: false
17: else
18:
19: let obj : Object = myType.InvokeMember("Section", BindingFlags.Static ||| BindingFlags.GetProperty ||| BindingFlags.NonPublic, null, null, Array.zeroCreate 0)
20: if (null = obj) then
21: strError <- "Could not invoke Section member"
22: false
23: else
24:
25: // If it's not already set, set it.
26: let fi : FieldInfo = myType.GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic ||| BindingFlags.Instance)
27: if(null = fi) then
28: strError <- "Could not access useUnsafeHeaderParsing field"
29: false
30: else
31:
32: if (not(Convert.ToBoolean(fi.GetValue(obj)))) then
33: fi.SetValue(obj, true)
34:
35: // Now return true
36: true
VB (Visual Basic):
1: Option Explicit On
2: Option Strict On
3: Imports System
4: Imports System.Reflection
5:
6: Public Class CUUHP_VB
7: Public Shared Function UseUnsafeHeaderParsing(ByRef strError As String) As Boolean
8:
9: Dim assembly As [Assembly]
10: assembly = [assembly].GetAssembly(GetType(System.Net.Configuration.SettingsSection))
11:
12: If (assembly Is Nothing) Then
13: strError = "Could not access Assembly"
14: Return False
15: End If
16:
17: Dim type As Type
18: type = [assembly].GetType("System.Net.Configuration.SettingsSectionInternal")
19: If (type Is Nothing) Then
20: strError = "Could not access internal settings"
21: Return False
22: End If
23:
24: Dim obj As Object
25: obj = [type].InvokeMember("Section", _
26: BindingFlags.Static Or BindingFlags.GetProperty Or BindingFlags.NonPublic, _
27: Nothing, Nothing, New [Object]() {})
28:
29: If (obj Is Nothing) Then
30: strError = "Could not invoke Section member"
31: Return False
32: End If
33:
34: ' If it's not already set, set it.
35: Dim fi As FieldInfo
36: fi = [type].GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic Or BindingFlags.Instance)
37: If (fi Is Nothing) Then
38: strError = "Could not access useUnsafeHeaderParsing field"
39: Return False
40: End If
41:
42: If (Not Convert.ToBoolean(fi.GetValue(obj))) Then
43: fi.SetValue(obj, True)
44: End If
45:
46: Return True
47: End Function
48: End Class