Compressed content in the response is indicated in the `Content-Encoding`.  The `Content-Type` should remain the same, that is, it should reflect the underlying media type that is compressed.

    Content-Type: application/javascript
    Content-Encoding: gzip

See sections [14.11 Content-Encoding](https://www.rfc-editor.org/rfc/rfc2616#section-14.11) and [3.5 Content Codings](https://www.rfc-editor.org/rfc/rfc2616#section-3.5) of RFC 2616 for more information.


I&#39;m running `bundle install` and I&#39;m getting this error:

    Building nokogiri using system libraries.
    
    Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
    
        /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby extconf.rb --use-system-libraries
    Building nokogiri using system libraries.
    libxml2 version 2.6.21 or later is required!
    *** extconf.rb failed ***
    Could not create Makefile due to some reason, probably lack of necessary
    libraries and/or headers.  Check the mkmf.log file for more details.  You may
    need configuration options.
    
    Provided configuration options:
    	--with-opt-dir
    	--without-opt-dir
    	--with-opt-include
    	--without-opt-include=${opt-dir}/include
    	--with-opt-lib
    	--without-opt-lib=${opt-dir}/lib
    	--with-make-prog
    	--without-make-prog
    	--srcdir=.
    	--curdir
    	--ruby=/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby
    	--help
    	--clean
    	--use-system-libraries
    	--with-zlib-dir
    	--without-zlib-dir
    	--with-zlib-include
    	--without-zlib-include=${zlib-dir}/include
    	--with-zlib-lib
    	--without-zlib-lib=${zlib-dir}/lib
    	--with-xml2-dir
    	--without-xml2-dir
    	--with-xml2-include
    	--without-xml2-include=${xml2-dir}/include
    	--with-xml2-lib
    	--without-xml2-lib=${xml2-dir}/lib
    	--with-libxml-2.0-config
    	--without-libxml-2.0-config
    	--with-pkg-config
    	--without-pkg-config
    	--with-xslt-dir
    	--without-xslt-dir
    	--with-xslt-include
    	--without-xslt-include=${xslt-dir}/include
    	--with-xslt-lib
    	--without-xslt-lib=${xslt-dir}/lib
    	--with-libxslt-config
    	--without-libxslt-config
    	--with-pkg-config
    	--without-pkg-config
    	--with-exslt-dir
    	--without-exslt-dir
    	--with-exslt-include
    	--without-exslt-include=${exslt-dir}/include
    	--with-exslt-lib
    	--without-exslt-lib=${exslt-dir}/lib
    	--with-libexslt-config
    	--without-libexslt-config
    	--with-pkg-config
    	--without-pkg-config
    
    extconf failed, exit code 1
    
    Gem files will remain installed in /Users/myuser/projectpath/vendor/bundle/ruby/2.0.0/gems/nokogiri-1.6.2.rc2 for inspection.
    Results logged to /Users/myuser/projectpath/vendor/bundle/ruby/2.0.0/extensions/universal-darwin-13/2.0.0/nokogiri-1.6.2.rc2/gem_make.out
    An error occurred while installing nokogiri (1.6.2.rc2), and Bundler cannot continue.
    Make sure that `gem install nokogiri -v &#39;1.6.2.rc2&#39;` succeeds before bundling.

Any ideas what could this be?

EDIT:
=== 

I also have installed nokogiri following the [instructions in the tutorial][1], and the weird thing is that the gem was successfully installed. When I run `gem list`, I have `nokogiri (1.6.2.1)`, but when running `bundle install` it displays the error.

[1]:http://nokogiri.org/tutorials/installing_nokogiri.html

Nokogiri &#39;Failed to build gem native extension&#39; when I run bundle install

I am new with ```Express```. As ```Express 4.x``` has removed bundled middlewares.
Any middleware I want to use should be required. When I read the README with [express-session][1] and [cookie-session][2] on github, I feel it hard to understand the difference.

So I try to write simple code to figure it out. I run twice for each middleware.

    var express = require(&#39;express&#39;)
	  , cookieParser = require(&#39;cookie-parser&#39;)
	  , session = require(&#39;cookie-session&#39;)
	  , express_sess = require(&#39;express-session&#39;)
	  , app = express();

	app.use(cookieParser())
	app.use(session({ keys: [&#39;abc&#39;], name: &#39;user&#39; }));
	//app.use(express_sess({ secret: &#39;abc&#39;, key: &#39;user&#39;}));
	app.get(&#39;/&#39;, function (req, res, next) {
		res.end(JSON.stringify(req.cookies));
		console.log(req.session)
		console.log(req.cookies)
	});

	app.listen(3000);

For ```cookie-session```, I always get {} in my terminal.

For ```express-session```, I get things like this.

    req.session: { cookie: { 
         path: &#39;/&#39;,
         _expires: null,
         originalMaxAge: null,
         httpOnly: true 
       } 
    }

    req.cookie: {user: &#39;s:aJ97vKA5CCwxqdTj0AV1siRQ.fWusS5+qfCKICtwkfrzcZ/Gq8P0Qdx/kx8mTBhoOhGU&#39;}

It really confuses me. So how to explain the result with the basic use? And what&#39;s the difference between them? When should I use them? 



  [1]: https://github.com/expressjs/session
  [2]: https://github.com/expressjs/cookie-session

What&#39;s difference with express-session and cookie-session?

I&#39;m serving gzipped copies of my css / javascript files. As per a tutorial, I set the content-type as `application/gzip` when serving these files. However, chrome doesn&#39;t seem to un-gzip these files, and for the javascript files I get a lot of &#39;illegal character&#39; errors. If I view source, I still see the files as compressed, rather than uncompressed.

My question is, what should I set as the content type for these files, in order for the browser to interpret them correctly as gzipped css / js files, and un-gzip them? If I just set `text/javascript` or `text/css`, will the browser still interpret them correctly?

Edit: Full response headers:

    HTTP/1.1 200 OK
    x-amz-id-2: UIBkZT/MuFxsmn+3nVOzEO63rRY99l3traCbMExUgSdGHUrOIPtNp34h1+ujYKmt
    x-amz-request-id: 19346C9B01D8FC62
    Date: Mon, 12 May 2014 03:59:51 GMT
    Content-Encoding: gzip
    Last-Modified: Mon, 12 May 2014 02:24:54 GMT
    ETag: &quot;561080b5e19f6daea2e74fd5a0623c79&quot;
    Accept-Ranges: bytes
    Content-Type: application/x-gzip
    Content-Length: 5153
    Server: AmazonS3



What &#39;Content-Type&#39; header to use when serving gzipped files?

I'm serving gzipped copies of my css / javascript files. As per a tutorial, I set the content-type as <code>application/gzip</code> when serving these files. However, chrome doesn't seem to un-gzip these files, and for the javascript files I get a lot of 'illegal character' errors. If I view source, I still see the files as compressed, rather than uncompressed.
My question is, what should I set as the content type for these files, in order for the browser to interpret them correctly as gzipped css / js files, and un-gzip them? If I just set <code>text/javascript</code> or <code>text/css</code>, will the browser still interpret them correctly?
Edit: Full response headers:
<pre><code class="hljs language-yaml">HTTP/1.1 200 OK
x-amz-id-2: UIBkZT/MuFxsmn+3nVOzEO63rRY99l3traCbMExUgSdGHUrOIPtNp34h1+ujYKmt
x-amz-request-id: 19346C9B01D8FC62
Date: Mon, 12 May 2014 03:59:51 GMT
Content-Encoding: gzip
Last-Modified: Mon, 12 May 2014 02:24:54 GMT
ETag: "561080b5e19f6daea2e74fd5a0623c79"
Accept-Ranges: bytes
Content-Type: application/x-gzip
Content-Length: 5153
Server: AmazonS3
</code></pre>

I have this sample data returned from an API.
 
I&#39;m using Lodash&#39;s `_.groupBy` to convert the data into an object I can use better.
The raw data returned is this:

    [
        {
            &quot;name&quot;: &quot;jim&quot;,
            &quot;color&quot;: &quot;blue&quot;,
            &quot;age&quot;: &quot;22&quot;
        },
        {
            &quot;name&quot;: &quot;Sam&quot;,
            &quot;color&quot;: &quot;blue&quot;,
            &quot;age&quot;: &quot;33&quot;
        },
        {
            &quot;name&quot;: &quot;eddie&quot;,
            &quot;color&quot;: &quot;green&quot;,
            &quot;age&quot;: &quot;77&quot;
        }
    ]

I want the `_.groupBy` function to return an object that looks like this:

    [
        {
            color: &quot;blue&quot;,
            users: [
                {
                    &quot;name&quot;: &quot;jim&quot;,
                    &quot;color&quot;: &quot;blue&quot;,
                    &quot;age&quot;: &quot;22&quot;
                },
                {
                    &quot;name&quot;: &quot;Sam&quot;,
                    &quot;color&quot;: &quot;blue&quot;,
                    &quot;age&quot;: &quot;33&quot;
                }
            ]
        },
        {
            color: &quot;green&quot;,
            users: [
                {
                    &quot;name&quot;: &quot;eddie&quot;,
                    &quot;color&quot;: &quot;green&quot;,
                    &quot;age&quot;: &quot;77&quot;
                }
            ]
        }
    ]

Currently I&#39;m using 

    _.groupBy(a, function(b) { return b.color})

which is returning this.

    {blue: [{..}], green: [{...}]}

the groupings are correct, but I&#39;d really like to add the keys I want (`color`, `users`). is this possible using `_.groupBy`? or some other `LoDash` utility?

using lodash .groupBy. how to add your own keys for grouped output?

Basically, I am using javascript to scrape data from Google Play store using:
 
1-Request

2-Cheerios

3-QueryString

I used Google Market API from Github which uses require as following:

    var request   = require(&#39;request&#39;);
    var cheerio   = require(&#39;cheerio&#39;);
    var qs      = require(&#39;querystring&#39;);

But I am getting the following 

ReferenceError: require is not defined ...

So, I don&#39;t have require in javascript which is either new for me or this is something out of the ordinary.



Javascript require() function giving ReferenceError: require is not defined

I&#39;ve seen plenty of questions that suggest using:

    for (var i = 0; i &lt; myArray.length; i++){ /* ... */ }

instead of:

    for (var i in myArray){ /* ... */ }

for arrays, due to inconsistent iteration ([see here](https://stackoverflow.com/questions/242841/javascript-for-in-vs-for)).

----

However, I can&#39;t seem to find anything that seems to prefer the object oriented loop:

    myArray.forEach(function(item, index){ /* ... */ });

Which seems way more intuitive to me.

For my current project, IE8 compatibilty is important, and I&#39;m considering using [Mozilla&#39;s polyfill](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach#Polyfill), however I&#39;m not 100% sure how this will work.

 - Are there any differences between the standard for loop (the first example above) and the Array.prototype.forEach implementation by modern browsers?
 - Are there any difference between modern browser implementations and Mozilla&#39;s implementation linked to above (with special regard to IE8)?
 - Performance is not as much of an issue, just consistency with which properties are iterated over.

JavaScript - Nuances of myArray.forEach vs for loop

I am building something with React where I need to insert HTML with React Variables in JSX. Is there a way to have a variable like so:

    var thisIsMyCopy = &#39;&lt;p&gt;copy copy copy &lt;strong&gt;strong copy&lt;/strong&gt;&lt;/p&gt;&#39;;

and to insert it into react like so, and have it work?

    render: function() {
        return (
            &lt;div className=&quot;content&quot;&gt;{thisIsMyCopy}&lt;/div&gt;
        );
    }

and have it insert the HTML as expected? I haven&#39;t seen or heard anything about a react function that could do this inline, or a method of parsing things that would allow this to work.

Insert HTML with React Variable Statements (JSX)

I have a problem that requires me to take two times in 12 hour format and compare them, we have moment.js included in our project and we initially thought it would be as trivial as this:

    var beginningTime = moment(&#39;8:45am&#39;);
    var endTime = moment(&#39;9:00am&#39;);
    console.log(beginningTime.isBefore(endTime)); //false???

**Fiddle:** http://jsfiddle.net/KyleMuir/M4R4z/

Is there something we are missing? It feels like this shouldn&#39;t be a hard problem to solve. When we perform any moment functions on our `beginningTime` or `endTime` it simply says `NAN`

Comparing two times with Moment JS

It looks like implementing basic HTTP authentication with Express v3 was trivial:

    app.use(express.basicAuth(&#39;username&#39;, &#39;password&#39;));

Version 4 (I&#39;m using 4.2) removed the `basicAuth` middleware, though, so I&#39;m a little stuck. I have the following code, but it doesn&#39;t cause the browser to prompt the user for credentials, which is what I&#39;d like (and what I imagine the old method did):

    app.use(function(req, res, next) {
        var user = auth(req);
        
        if (user === undefined || user[&#39;name&#39;] !== &#39;username&#39; || user[&#39;pass&#39;] !== &#39;password&#39;) {
            res.writeHead(401, &#39;Access invalid for user&#39;, {&#39;Content-Type&#39; : &#39;text/plain&#39;});
            res.end(&#39;Invalid credentials&#39;);
        } else {
            next();
        }
    });



Basic HTTP authentication with Node and Express 4

I&#39;ve got a browser game and I have recently started adding audio to the game. 

Chrome does not load the whole page and gets stuck at `&quot;91 requests | 8.1 MB transferred&quot;` and does not load any more content; and it even breaks the website in all other tabs, saying `Waiting for available socket`. 

After 5 mins (exactly) the data are loaded. 

![enter image description here][1]

![enter image description here][2]

This does not happen on any other browser.

Removing one MP3 file (the latest added one) fixed the problem, so is it perhaps a data limit problem?


  [1]: http://i.stack.imgur.com/ZutCF.png
  [2]: http://i.stack.imgur.com/FEW4q.png

Chrome hangs after certain amount of data transfered - waiting for available socket

I have to validate the `Content-Type` header value before passing it to an HTTP request.

Is there a specific list for all the possible values of `Content-Type`?

Otherwise, is there a way to validate the content type before using it in an HTTP request?


What are all the possible values for HTTP &quot;Content-Type&quot; header?

I&#39;m looking into what is the correct way to pass multiple values for the same parameter name in a GET request.

I&#39;ve seen URLs like this:

    http://server/action?id=a&amp;id=b

And I&#39;ve seen URLs like this:

    http://server/action?id=a,b

My understanding is that the first is correct, but I can&#39;t find any reference for this. I had a look at the http spec but couldn&#39;t see anything about how the &#39;query&#39; part of a URL should be made up.

I don&#39;t want an answer that says &quot;either is fine&quot; - if I&#39;m building a webservice, I want to know which of these methods is standard so that people using my webservice know how to pass multiple parameters for the same name.

So, can someone point me at an official reference source to confirm which option is correct?

Correct way to pass multiple values for same parameter name in GET request

I want to design my rest endpoint with the appropriate method for the following scenario.

There is a group. Each group has a status. The group can be activated or inactivated by the admin.

Should I design my end point as 

    PUT /groups/api/v1/groups/{group id}/status/activate

OR

    PATCH /groups/api/v1/groups/{group id}

    with request body like 
    {action:activate|deactivate}

Should I use PATCH or PUT in my REST API?

**Update** 20140702:

- [The solution](https://stackoverflow.com/a/24523253/194982)
- [Detailed answer as a blog post](http://blog.bguiz.com/2014/07/03/file-download-with-http-request-header/)

(but I&#39;m marking one of the other answers as accepted instead of my own,
as it got me halfway there, and to reward the effort)

----

It appears that setting a HTTP request header is not possible through links with `&lt;a href=&quot;...&quot;&gt;`, and can only be done using `XMLHttpRequest`.

However, the URL linked to is a file that should be downloaded (browser should not navigate to its URL), and I am not sure is this can be done using AJAX.

Additionally, the file being returned is a binary file, and AJAX is not intended for that.

How would one go about triggering a file download with a HTTP request that has a custom header added to it?

edit: fix broken link





How to set a header for a HTTP GET request, and trigger file download?

I&#39;m trying to understand how to use CORS and am confused about what the `Access-Control-Allow-Credentials` header does.

[The documentation][1] says

&gt; Indicates whether or not the response to the request can be exposed
&gt; when the credentials flag is true.

But I don&#39;t understand what the response being &quot;exposed&quot; means.

Can anyone explain what this header being set to true (in conjunction with the credentials flag being set to true) actually does?

  [1]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS

What exactly does the Access-Control-Allow-Credentials header do?

How to pass query params and headers in post method using HTTparty. I am doing as follows
But it throws 

    query = {:method =&gt; &quot;neworder&quot;, :nonce =&gt; 1404996028, :order_type =&gt; &quot;buy&quot;, :quantity=&gt;1,:rate=&gt;1}
    headers = {:key=&gt; &quot;87819747209090199871234&quot;, :sign=&gt; &quot;0a3888ac7f8e411ad73a0a503c55db70a291rsf34bfb9f9a47147d5200882674f717f6ede475669f3453&quot;}
    
    HTTParty.post(&quot;https://www.acb.com/api/v2/market/LTC_BTC/&quot;, :query =&gt; query, :headers =&gt; headers )

But it throws the following error. How to handle query string params and headers with HTTparty.

    /home/user/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/net/http/header.rb:172:in `capitalize&#39;: undefined method `split&#39; for :key:Symbol (NoMethodError)
    from /home/user/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/net/http/header.rb:165:in `block in each_capitalized&#39;
    from /home/user/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/net/http/header.rb:164:in `each&#39;
    from /home/user/.rvm/rubies/ruby-2.1.0/lib/ruby/2.1.0/net/http/header.rb:164:in `each_capitalized&#39;
	

Passing headers and query params in HTTparty

I have already googled a lot this subject, read various articles about this header, its use in Heroku, and projects based on Django.

However, it&#39;s still all confused in my head.

  - What is the purpose of this header?
  - Does it violate user privacy?
  - Can it help tracking a user?

What is the X-REQUEST-ID http header?

I wanted to try out the python BytesIO class.

As an experiment I tried writing to a zip file in memory, and then reading the bytes back out of that zip file. So instead of passing in a file-object to `gzip`, I pass in a `BytesIO` object. Here is the entire script:

    from io import BytesIO
    import gzip

    # write bytes to zip file in memory
    myio = BytesIO()
    with gzip.GzipFile(fileobj=myio, mode=&#39;wb&#39;) as g:
        g.write(b&quot;does it work&quot;)
    
    # read bytes from zip file in memory
    with gzip.GzipFile(fileobj=myio, mode=&#39;rb&#39;) as g:
        result = g.read()

    print(result)

But it is returning an empty `bytes` object for `result`. This happens in both Python 2.7 and 3.4. What am I missing?


Writing then reading in-memory bytes (BytesIO) gives a blank result

I understand that GZIP is a combination of LZ77 and Huffman coding and can be configured with a level between 1-9 where 1 indicates  the  fastest  compression (less  compression) and 9 indicates the slowest compression method (best  compression).

My question is, does the choice of level **only** impact the compression process or is there an additional cost also incurred in decompression depending on the level used to compress?

I ask because typically many web servers will GZIP responses on the fly if the client supports it, e.g. `Accept-Encoding: gzip`. I appreciate that when doing this on the fly a level such as 6 might be the good choice for the average case, since it gives a good balance between speed and compression. 

However, if I have a bunch of static assets that I can GZIP just once ahead of time - and never need to do this again - would there be any downside to using the highest but slowest compression level? I.e. is there now an additional overhead for the client that would not have been incurred had a lower compression level been used.


Does GZIP Compression Level Have Any Impact On Decompression

I am trying to make a script for unzipping all the .tar.gz files from folders in one directory. For example, I will have a file which it calls ( testing.tar.gz). Then if I do manually, I can press to &quot;extract here&quot; then the .tar.gz file will create a new file, and it calls testing.tar. Finally, if I repeat the process of pressing &quot;extract here&quot;, the .tar file prodcudes me all the .pdf files.

I wonder that how can I do it, and I have my code here and it seems doesn&#39;t realty work tho.

    import os
    import tarfile
    import zipfile

    def extract_file(path, to_directory=&#39;.&#39;):
        if path.endswith(&#39;.zip&#39;):
            opener, mode = zipfile.ZipFile, &#39;r&#39;
        elif path.endswith(&#39;.tar.gz&#39;) or path.endswith(&#39;.tgz&#39;):
            opener, mode = tarfile.open, &#39;r:gz&#39;
        elif path.endswith(&#39;.tar.bz2&#39;) or path.endswith(&#39;.tbz&#39;):
            opener, mode = tarfile.open, &#39;r:bz2&#39;
        else: 
            raise ValueError, &quot;Could not extract `%s` as no appropriate extractor is found&quot; % path
    
        cwd = os.getcwd()
        os.chdir(to_directory)
    
        try:
            file = opener(path, mode)
            try: file.extractall()
            finally: file.close()
        finally:
            os.chdir(cwd)


I want to create a script for unzip (.tar.gz) file via (Python)

I need to extract a gz file that I have downloaded from an FTP site to a local Windows file server. I have the variables set for the local path of the file, and I know it can be used by GZIP muddle. 

How can I do this? The file inside the GZ file is an XML file. 


How to unzip gz file using Python



I am trying to write a dataframe to a gzipped csv in python pandas, using the following:

    import pandas as pd
    import datetime
    import csv
    import gzip

    # Get data (with previous connection and script variables)
    df = pd.read_sql_query(script, conn)

    # Create today&#39;s date, to append to file
    todaysdatestring = str(datetime.datetime.today().strftime(&#39;%Y%m%d&#39;))
    print todaysdatestring

    # Create csv with gzip compression
    df.to_csv(&#39;foo-%s.csv.gz&#39; % todaysdatestring,
          sep=&#39;|&#39;,
          header=True,
          index=False,
          quoting=csv.QUOTE_ALL,
          compression=&#39;gzip&#39;,
          quotechar=&#39;&quot;&#39;,
          doublequote=True,
          line_terminator=&#39;\n&#39;)

This just creates a csv called &#39;foo-YYYYMMDD.csv.gz&#39;, not an actual gzip archive.

I&#39;ve also tried adding this:

    #Turn to_csv statement into a variable
    d = df.to_csv(&#39;foo-%s.csv.gz&#39; % todaysdatestring,
          sep=&#39;|&#39;,
          header=True,
          index=False,
          quoting=csv.QUOTE_ALL,
          compression=&#39;gzip&#39;,
          quotechar=&#39;&quot;&#39;,
          doublequote=True,
          line_terminator=&#39;\n&#39;)

    # Write above variable to gzip
     with gzip.open(&#39;foo-%s.csv.gz&#39; % todaysdatestring, &#39;wb&#39;) as output:
       output.write(d)


Which fails as well. Any ideas? 

    

Content Type	Original Author	Original Content on Stackoverflow
Question	Ali	View Question on Stackoverflow
Solution 1 - Javascript	Joel Allison	View Answer on Stackoverflow

What 'Content-Type' header to use when serving gzipped files?

Javascript Problem Overview

Javascript Solutions

Solution 1 - Javascript

What's difference with express-session and cookie-session?

Nokogiri 'Failed to build gem native extension' when I run bundle install

Attributions