问题
In Firebug the request header has the following entry:
Accept-Encoding: gzip, deflate
But there's no:
Content-Encoding: gzip
In the Response Header.
Regardless of anything I've tried, following a number of answers on SO and other sites, nothing seems to work! Neither static nor dynamic files are being compressed, or at least if they are there's no content encoding - gzip value coming back in the response header.
Here's an example of my web.config settings:
<urlCompression doDynamicCompression="true" doStaticCompression="true" dynamicCompressionBeforeCache="true" />
<httpCompression directory="%SystemDrive%\inetpub\temp\IIS Temporary Compressed Files" minFileSizeForComp="150" staticCompressionIgnoreHitFrequency="true">
<remove name="gzip" />
<scheme name="gzip" dll="%Windir%\system32\inetsrv\gzip.dll" staticCompressionLevel="8" dynamicCompressionLevel="8" />
</httpCompression>
I've ignored the hit frequencystaticCompressionIgnoreHitFrequency="true"
I've confirmed that IIS is in fact compressing the files which I can see in:
C:\inetpub\temp\IIS Temporary Compressed Files
As specified here: set up gzip in IIS 8 windows 8
I've ensured that static and dynamic compression is enabled in Windows Features > Internet Information Services > WWW Services > Performance Features
I've also tried this guy's approach:
IIS 7.5 Compression creates compressed file but returns the non-compressed one
Edit 1:
IIS version is 10 but I have also tried this on IIS 8.5
Edit 2:
I've now also tried various configuration files found at this link:
https://github.com/h5bp/server-configs-iis/ which provides what looks like some 'best practice' web.config files.
Not solved
Edit 3:
Based on @Nkosi's input I created a completely new Asp.net MVC application and configured it using all these options I've tried.
Here's the raw header that I got from Fiddler:
HTTP/1.1 200 OK
Transfer-Encoding: chunked
Content-Type: text/javascript; charset=UTF-8
Expires: Wed, 20 Jul 2016 18:22:47 GMT
Last-Modified: Wed, 20 Jul 2016 18:22:47 GMT
Server: Microsoft-HTTPAPI/2.0
Date: Wed, 20 Jul 2016 18:22:47 GMT
As you can see, no Content-Encoding: Gzip
Not solved
Edit 4:
I've tried this approach of adding code to the BeginRequest event in the Global.asax section: https://stackoverflow.com/a/27185575/392591
Not solved
Edit 5:
So I just tried enabling tracing based on this answer on SO: https://stackoverflow.com/a/33182525/392591
No failures, but I did notice right at the bottom of the trace file there's a section called GENERAL_RESPONSE_HEADERS and here's what it provides:
Cache-Control: private
Content-Type: text/html; charset=utf-8
Content-Encoding: gzip
Server: Microsoft-IIS/10.0
X-AspNetMvc-Version: 5.2
X-AspNet-Version: 4.0.30319
X-Powered-By: My Little Pony
X-UA-Compatible: IE=Edge,chrome=1
And that's for every static type file.
However I just found the following in the trace file:
8. STATIC_COMPRESSION_START 08:04:03.552
9. STATIC_COMPRESSION_NOT_SUCCESS Reason="NOT_FREQUENTLY_HIT" 08:04:03.552
10. STATIC_COMPRESSION_END 08:04:03.552
Compression Not Success for the reason Not Frequently Hit... Odd because I definitely have the Ignore Hit Frequency option set to true!
So I just went into IIS Manager and on the server I set the Ignore Hit Frequency to true (i.e. applicationHost.config) and it changed the trace file output to the following:
8. STATIC_COMPRESSION_START 08:19:17.489
9. STATIC_COMPRESSION_SUCCESS 08:19:17.489
10. STATIC_COMPRESSION_END 08:19:17.489
I went back and switched it off in the applicationHost.config and it went back to a Static Compression Not Success, so this definitely makes a difference. However, when I look at FireBug, it's still delivery the uncompressed file and no GZIP Content Encoding response header.
Another interesting bit I noticed in the Failed Request Trace is the final two entires GENERAL_FLUSH_RESPONSE_END and GENERAL_REQUEST_END both of which show my Bootstrap.css file as having sent 17903 bytes, roughly 18kb, matching the compressed version of the file I see in my IIS Temporary Compressed Files folder. So the file is physically being compressed and according to Failed Request traces it's sending down the right content... but then the browser picks up the full 117kb file instead?
Not solved
回答1:
I am using IIS10 and my web.config has
<system.webServer>
<urlCompression doDynamicCompression="true" doStaticCompression="true" dynamicCompressionBeforeCache="false" />
<!-- other config removed for brevity -->
</system.webServer>
When I do test requests from a browser (Firefox, IE11, Edge, Google Chrome) to a simple MVC application.
The requests all have Accept-Encoding: gzip, deflate and the responses return Content-Encoding:gzip.
I Even tested it with Fiddler. Composing the request manually
GET http://localhost/MyWebApplication HTTP/1.1
User-Agent: Fiddler
Host: localhost
Accept-Encoding: gzip, deflate
and get the same result
HTTP/1.1 200 OK
Cache-Control: private
Content-Type: text/html; charset=utf-8
Content-Encoding: gzip
Vary: Accept-Encoding
Server: Microsoft-IIS/10.0
X-AspNetMvc-Version: 5.2
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Date: Mon, 18 Jul 2016 15:26:06 GMT
Content-Length: 3826
...
Css, Js and all other text based files are being compressed.
You may need to re-check your configuration to make sure you have the compression properly configured in IIS and your web.config.
UPDATE:
I did notice that images were not being compressed
Request
GET http://localhost/MyWebApplication/Images/Logo_small.png HTTP/1.1
User-Agent: Fiddler
Host: localhost
Accept-Encoding: gzip, deflate
Response
HTTP/1.1 200 OK
Cache-Control: max-age=604800
Content-Type: image/png
Last-Modified: Fri, 27 Nov 2015 03:15:22 GMT
Accept-Ranges: bytes
ETag: "c9d1fdd9c128d11:0"
Server: Microsoft-IIS/10.0
X-Powered-By: ASP.NET
Date: Mon, 18 Jul 2016 15:33:02 GMT
Content-Length: 2970
...
And after some google-fu found out that the images are usually already compressed so gzip was not applied.
FULL system.webServer from web.config
<system.webServer>
<urlCompression doDynamicCompression="true" doStaticCompression="true" dynamicCompressionBeforeCache="false" />
<validation validateIntegratedModeConfiguration="false" />
<httpErrors errorMode="Custom" existingResponse="Replace">
<clear />
<error statusCode="404" responseMode="ExecuteURL" path="/NotFound" />
</httpErrors>
<handlers>
<remove name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" />
<remove name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" />
<remove name="ExtensionlessUrlHandler-Integrated-4.0" />
<remove name="OPTIONSVerbHandler" />
<remove name="TRACEVerbHandler" />
<add name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
<add name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
<add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
</handlers>
<staticContent>
<remove fileExtension=".woff" />
<remove fileExtension=".woff2" />
<mimeMap fileExtension=".woff" mimeType="application/font-woff" />
<mimeMap fileExtension=".woff2" mimeType="application/font-woff2" />
<clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="7.00:00:00" />
</staticContent>
</system.webServer>
回答2:
I've had a similar issue with a pre configured IIS.
After many attempts, we figured out that the problem was a bug in GZIP installation, the problem was solved simply by reinstalling the feature in control panel.
回答3:
I have similar situation with IIS and gzip configuration
In Firebug the request header has the following entry: Accept-Encoding: gzip, deflate
But there's no: Content-Encoding: gzip In the Response Header.
In my case problem was with antivirus protection. Actually gzipping was applied but antivirus with enabled settings protect http connections (depends on concrete program), unzip response check it and after that rewrite response headers on the fly.
NOTE: A key attribute when some proxy/antivirus changed your response headers, it is when disappear Content-Length and Transfer-Encoding is added with value chunked.
回答4:
I have just had the same problem. The cause ended up being the dynamicCompressionBeforeCache="true" setting. Changing this attribute to "false" fixed the problem.
<urlCompression doDynamicCompression="true" doStaticCompression="true" dynamicCompressionBeforeCache="false" />
I run a few sites on a shared server provided by SmarterASP.Net. I raised a support ticket with them and along the way I determined dynamicCompressionBeforeCache="true" to be the culprit.
I pointed them to the Microsoft documentation covering this attribute, at https://docs.microsoft.com/en-us/iis/configuration/system.webserver/urlcompression, and asked them why a setting of "true" would be causing this issue.
SmarterASP.Net support referred to a section of the documentation stating...
If the dynamicCompressionBeforeCache attribute is true when the output cache response has been flushed, dynamic compression will not be performed before the response is put into the output cache.
...and they said...
"We do not save output cache in our server end. So the output cache responses always got flushed and caused the issue."
I can't say that I fully understand the mechanics here, or why SmarterASP.Net don't save the output cache. But a setting of dynamicCompressionBeforeCache="false" definitely solved the problem for me.
来源：https://stackoverflow.com/questions/38250376/iis-application-missing-content-encoding-gzip-in-response-header