Split fever & greader into two separate pages. (#3905)

* [docs] add newsflash to fever-clients

* [docs] split fever&greader-apis into two pages and make the more consistent

3 files changed, 71 insertions, 3 deletions

diff --git a/docs/en/developers/01_Index.md b/docs/en/developers/01_Index.md
index 56a807a6f..94339f7cb 100644
--- a/docs/en/developers/01_Index.md
+++ b/docs/en/developers/01_Index.md
@@ -12,6 +12,7 @@ Start by creating your development environment. A guide to setting up FreshRSS's
 * [Releasing a new version](05_Release_new_version.md)
 * [Reporting bugs](06_Reporting_Bugs.md)
 * [Fever API](06_Fever_API.md)
+* [GoogleReader API](06_GoogleReader_API.md)
 
 ## Backend Development
 
diff --git a/docs/en/developers/06_Fever_API.md b/docs/en/developers/06_Fever_API.md
index ad5e3efd1..bcd9db660 100644
--- a/docs/en/developers/06_Fever_API.md
+++ b/docs/en/developers/06_Fever_API.md
@@ -1,7 +1,8 @@
 # FreshRSS - Fever API implementation
 
-See the [page about our Google Reader compatible API](06_Mobile_access.md) for another possibility
-and general aspects of API access.
+See [Mobile access](../users/06_Mobile_access.md) for general aspects of API access.
+Additionally [page about our Google Reader compatible API](06_GoogleReader_API.md) for another possibility.
+
 
 ## RSS clients
 
@@ -11,7 +12,7 @@ But we can **only** do that for free clients.
 
 ### Usage & Authentication
 
-Before you can start using this API, you have to enable and setup API access, which is [documented here](https://freshrss.github.io/FreshRSS/en/users/06_Mobile_access.html),
+Before you can start using this API, you have to enable and setup API access, which is [documented here](../users/06_Mobile_access.md),
 and then reset the user’s API password.
 
 Then point your mobile application to the `fever.php` address (e.g. `https://freshrss.example.net/api/fever.php`).
@@ -22,6 +23,7 @@ Then point your mobile application to the `fever.php` address (e.g. `https://fre
 |:----------------------------------------------------------------------------------:|:-------------------:|:--------------------------------------------------------:|
 |[Fluent Reader](https://hyliu.me/fluent-reader/)                                    |Windows, Linux, macOS|[BSD-3-Clause](https://github.com/yang991178/fluent-reader/blob/master/LICENSE)|
 |[Fiery Feeds](https://apps.apple.com/app/fiery-feeds-rss-reader/id1158763303)       |iOS                  |Closed Source                                             |
+|[Newsflash](https://gitlab.com/news-flash/news_flash_gtk/)                          |Linux                |[GPLv3](https://gitlab.com/news-flash/news_flash_gtk/-/blob/master/LICENSE)|
 |[Unread](https://apps.apple.com/app/unread-rss-reader/id1252376153)                 |iOS                  |Closed Source                                             |
 |[Reeder](https://www.reederapp.com/)                                                |iOS                  |Closed Source                                              |
 |[ReadKit](https://apps.apple.com/app/readkit/id588726889)                           |macOS                |Closed Source                                              |
diff --git a/docs/en/developers/06_GoogleReader_API.md b/docs/en/developers/06_GoogleReader_API.md
new file mode 100644
index 000000000..823b4c8b0
--- /dev/null
+++ b/docs/en/developers/06_GoogleReader_API.md
@@ -0,0 +1,65 @@
+# FreshRSS - Google Reader compatible API implementation
+
+See [Mobile access](../users/06_Mobile_access.md) for general aspects of API access.
+Additionally [page about our Fever compatible API](06_Fever_API.md) for another possibility.
+
+## RSS clients
+
+There are many RSS clients that support the Fever API, but they seem to understand the Fever API a bit differently.
+If your favourite client doesn't work properly with this API, please create an issue and we'll have a look.
+But we can **only** do that for free clients.
+
+### Usage & Authentication
+
+Before you can start using this API, you have to enable and setup API access, which is [documented here](../users/06_Mobile_access.md),
+and then reset the user’s API password.
+
+Then point your mobile application to the `greader.php` address (e.g. `https://freshrss.example.net/api/greader.php`).
+
+# Compatible clients
+
+6. On the same FreshRSS API page, note the address given under “Your API address”, like `https://freshrss.example.net/api/greader.php`
+	* Type the API address in a client, together with your FreshRSS username, and the corresponding special API password.
+
+| App                                                                                | Platform            | License                                            |
+|:----------------------------------------------------------------------------------:|:-------------------:|:--------------------------------------------------------:|
+|[News+](https://play.google.com/store/apps/details?id=com.noinnion.android.newsplus) with [News+ Google Reader extension](https://github.com/noinnion/newsplus/blob/master/apk/GoogleReaderCloneExtension_101.apk) |Android|Closed Source (Free)|
+|[FeedMe 3.5.3+](https://play.google.com/store/apps/details?id=com.seazon.feedme) |Android                  |Closed Source (Free)                                             |
+|[EasyRSS](https://github.com/Alkarex/EasyRSS)                          |Android                |[GPLv3](https://github.com/Alkarex/EasyRSS/blob/master/license.txt) ([F-Droid](https://f-droid.org/packages/org.freshrss.easyrss/))|
+|[Readrops](https://github.com/readrops/Readrops) |Android                  |[GPLv3](https://github.com/readrops/Readrops/blob/develop/LICENSE)                                             |
+|[FocusReader](https://play.google.com/store/apps/details?id=allen.town.focus.reader) |Android                  |Closed Source(Free)                                              |
+|[FeedReader 2.0+](https://jangernert.github.io/FeedReader/)                           |Linux                |[GPLv3](https://github.com/jangernert/FeedReader/blob/master/LICENSE)                                              |
+|[Newsboat 2.24+](https://newsboat.org/)                           |Linux                |[MIT](https://github.com/newsboat/newsboat/blob/master/LICENSE)                                              |
+|[Vienna RSS](http://www.vienna-rss.com/)                           |MacOS                |[Apache-2.0](https://github.com/ViennaRSS/vienna-rss/blob/master/LICENCE.md)                                              |
+|[Reeder](https://www.reederapp.com/)                           |MacOS, iOS                |Closed Source                                              |
+|[FreshRSS-Notify](https://addons.mozilla.org/firefox/addon/freshrss-notify-webextension/)                           |Firefox                |Open Source                                              |
+
+# Google Reader compatible API
+
+Examples of basic queries:
+
+```sh
+# Initial login, using API password (Email and Passwd can be given either as GET, or POST - better)
+curl 'https://freshrss.example.net/api/greader.php/accounts/ClientLogin?Email=alice&Passwd=Abcdef123456'
+SID=alice/8e6845e089457af25303abc6f53356eb60bdb5f8
+Auth=alice/8e6845e089457af25303abc6f53356eb60bdb5f8
+
+# Examples of read-only requests
+curl -s -H "Authorization:GoogleLogin auth=alice/8e6845e089457af25303abc6f53356eb60bdb5f8" \
+  'https://freshrss.example.net/api/greader.php/reader/api/0/subscription/list?output=json'
+
+curl -s -H "Authorization:GoogleLogin auth=alice/8e6845e089457af25303abc6f53356eb60bdb5f8" \
+  'https://freshrss.example.net/api/greader.php/reader/api/0/unread-count?output=json'
+
+curl -s -H "Authorization:GoogleLogin auth=alice/8e6845e089457af25303abc6f53356eb60bdb5f8" \
+  'https://freshrss.example.net/api/greader.php/reader/api/0/tag/list?output=json'
+
+# Retrieve a token for requests making modifications
+curl -H "Authorization:GoogleLogin auth=alice/8e6845e089457af25303abc6f53356eb60bdb5f8" \
+  'https://freshrss.example.net/api/greader.php/reader/api/0/token'
+8e6845e089457af25303abc6f53356eb60bdb5f8ZZZZZZZZZZZZZZZZZ
+
+# Get articles, piped to jq for easier JSON reading
+curl -s -H "Authorization:GoogleLogin auth=alice/8e6845e089457af25303abc6f53356eb60bdb5f8" \
+  'https://freshrss.example.net/api/greader.php/reader/api/0/stream/contents/reading-list' | jq .
+```