compression: moved around

- moved it from "downloads" to "transfer control"
- made that section generic about compression and link to the HTTP one
- create a new HTTP compression page under custom HTTP

Closes #486

SUMMARY.md

@@ -87,7 +87,6 @@
     * [Download to a file named by the URL](usingcurl/downloads/url-named.md)
     * [Use the target filename from the server](usingcurl/downloads/content-disp.md)
     * [HTML and charsets](usingcurl/downloads/charsets.md)
-    * [Compression](usingcurl/downloads/compression.md)
     * [Shell redirects](usingcurl/downloads/redirects.md)
     * [Multiple downloads](usingcurl/downloads/multiple.md)
     * [My browser shows something else](usingcurl/downloads/browsers.md)
@@ -101,6 +100,7 @@
     * [Stop slow transfers](usingcurl/transfers/tooslow.md)
     * [Rate limiting](usingcurl/transfers/rate-limiting.md)
     * [Request rate limiting](usingcurl/transfers/request-rate.md)
+    * [Compression](usingcurl/transfers/compression.md)
   * [Connections](usingcurl/connections/README.md)
     * [Name resolve tricks](usingcurl/connections/name.md)
     * [Connection timeout](usingcurl/connections/timeout.md)
@@ -173,6 +173,7 @@
     * [User-agent](http/modify/user-agent.md)
     * [Ranges](http/modify/ranges.md)
     * [Conditionals](http/modify/conditionals.md)
+    * [Compression](http/modify/compression.md)
   * [HTTP PUT](http/put.md)
   * [Cookies](http/cookies/README.md)
     * [Cookie engine](http/cookies/engine.md)

http/modify/README.md

@@ -12,6 +12,7 @@ this chapter details how you can customize those.
 * [User-agent](user-agent.md)
 * [Ranges](ranges.md)
 * [Conditionals](conditionals.md)
+* [Compression](compression.md)
 
 Of course, changing the [HTTP version](../versions/) is another way to alter
 the request.

usingcurl/downloads/compression.md → http/modify/compression.md

@@ -1,7 +1,7 @@
 # Compression
 
-curl allows you to ask HTTP and HTTPS servers to provide compressed versions
-of the data and then perform automatic decompression of it on arrival. In
+curl supports asking HTTP and HTTPS servers to provide compressed versions of
+the data and then perform automatic decompression of it on arrival. In
 situations where bandwidth is more limited than CPU this helps you receive
 more data in a shorter amount of time.
 
@@ -41,7 +41,10 @@ hands are always compressed and cannot be sent uncompressed. However, as a
 convenience to users, curl always shows the headers uncompressed in a style
 similar to how they look for HTTP/1.x to make the output and look consistent.
 
-## Uploads
+## HTTP uploads
 
-For HTTP there is no standard way to do compression. The above mentioned HTTP
-compression methods only work for downloads.
+For HTTP uploads with POST or PUT there is no standard way to do compression.
+The above mentioned HTTP compression methods only work for downloads.
+
+You can of course still compress the data locally before sending it to the
+server.

usingcurl/downloads/README.md

@@ -12,7 +12,6 @@ specific data pointed to by a URL onto your machine.
 * [Download to a file named by the URL](url-named.md)
   * [Use the target filename from the server](content-disp.md)
 * [HTML and charsets](charsets.md)
-* [Compression](compression.md)
 * [Shell redirects](redirects.md)
 * [Multiple downloads](multiple.md)
 * [My browser shows something else](browsers.md)

usingcurl/transfers/README.md

@@ -7,3 +7,4 @@ multiple transfers.
  * [Stop slow transfers](tooslow.md)
  * [Rate limiting](rate-limiting.md)
  * [Request rate limiting](request-rate.md)
+ * [Compression](compression.md)

usingcurl/transfers/compression.md

@@ -0,0 +1,19 @@
+# Compression
+
+Automatic compression of data before it gets sent can help getting the data to
+the other end faster due to the reduced bandwidth needed.
+
+curl offers automatic compression and decompression for SFTP, SCP and HTTP(S).
+With HTTP(S) it is only possible to do it for downloads, while SFTP and SCP
+offer it for both directions.
+
+## For HTTP
+
+See [HTTP compression](../../http/modify/compression.md) for the details.
+
+## For SFTP/SCP
+
+Provide the `--compressed-ssh` option on the command line and the transfer
+will automatically and transparently use compression if it can. Like:
+
+    curl -O --compressed-ssh sftp://example.com/bigfile