readme update

README.md

 # vl-dcc
-DCC generation for the vacumm laboratory.
 
-## install & activate
+The DCC generation of the vacuum laboratory.
 
-Create a file `.git/hooks/pre-push` in the GIT repository with the following 
+## API
+
+### `vl-dcc/<cer_doc_id>` (GET)
+
+Returns a `xml` version (the DCC) of a pre-generated `json` document:
+
+```shell
+curl -s http://localhost:5006/vl-dcc/2019-75046 > dcc-2019-75046.xml
+```
+
+Returns the DCC and validation at once:
+
+```shell
+curl -s http://a73434:5006/vl-dcc/2019-75046 | \
+  curl -s -X POST -H "Content-Type: text/xml" -d @- http://a73434:5005/validate
+```
+
+### `update` (POST)
+
+The update endpoint pulls the latest program version from origin master
+
+```
+http://server:port/update
+```
+
+This URL has to be specified in the GitLab server under "Settings /
+Webhooks" (no secret token). "Tag Push Events" need to be activated. The
+following information sent by GitLab is evaluated in order to obtain
+all files of the repository:
+
+```json
+{
+  "repository": {
+    "homepage": "https://a75436.berlin.ptb.de/vaclab/vl-dcc",
+    "name": "vl-dcc"
+  }
+}
+```
+
+### `version` (GET)
+
+```shell
+curl -s http://localhost:5006/version
+```
+
+## Installation and activation
+
+Create a file `.git/hooks/pre-push` in the GIT repository with the following
 content:
 
 ```shell
 #!/bin/bash
 
-# In the case of "git push --tags", writes the short tag value to the 
+# In the case of "git push --tags", writes the short tag value to the
 # VERSION file in the top level directory of the Git repository
 
 toplevel=$(git rev-parse --show-toplevel)
@@ -38,7 +84,7 @@ Then make this file executable:
 chmod 755 .git/hooks/pre-push
 ```
 
-Do the following steps with root permission on the server installation:
+Do the following steps with root permission or sudo on the server installation:
 
 ```shell
 mkdir -p /usr/local/share/vl-dcc
@@ -46,7 +92,7 @@ cd /usr/local/share/vl-dcc
 curl --silent --insecure --output - \
   https://a75436.berlin.ptb.de/vaclab/vl-dcc/-/archive/master/vl-dcc-master.tar \
   | tar xf - --strip-components=1        # only once
-sudo apt install python3-pip             # openSUSE: sudo zypper in python3-pip 
+sudo apt install python3-pip             # openSUSE: sudo zypper in python3-pip
 python3 -m venv .
 source bin/activate
 pip3 install pip-tools
@@ -56,83 +102,37 @@ chown -R nobody.nogroup $PWD             # openSUSE: chown -R nobody.nobody $PWD
 systemctl daemon-reload                  # if already exist
 systemctl link $PWD/vl-dcc.service
 systemctl enable vl-dcc.service          # make permanent
-systemctl start vl-dcc.service      
+systemctl start vl-dcc.service
 systemctl status vl-dcc.service          # running?
 journalctl -f --unit vl-dcc.service      # run-time check
 ```
 
-## api
-
-### vl-dcc/<cer_doc_id> (GET)
-
-Returns a xml version of a certificate-document:
-
-```
-curl -s http://localhost:5006/vl-dcc/2019-75046 > dcc-2019-75046.xml
-```
-    
-Returns a xml version of a certificate-document with validation at once:
-
-```
-curl -s http://a73434:5006/vl-dcc/2019-75046 | \
-  curl -s -X POST -H "Content-Type: text/xml" -d @- http://a73434:5005/validate          
-```
- 
-### zz (GET)
-
-returns a xml version based on the dummy certificate-document (`zz.json`) 
-for test purpose. 
-
-```    
-curl -s http://localhost:5006/zz > zz.xml
-```
-
-### update (POST)
-
-pulls the latest program version from origin master
-
-```
-http://server:port/update
-```
-
-This URL must be specified in the GitLab server under "Settings / Webhooks" (no 
-secret token). "Tag Push Events" must be activated. The following information 
-sent by GitLab is evaluated in order to obtain all files of the Ropositorium 
-via the requested tar stream:
-
-```json
-{
-  ...
-  "repository": {
-    "homepage": "https://a75436.berlin.ptb.de/vaclab/vl-dcc",
-    "name": "vl-dcc"
-  }
-  ...
-}
-```
-
-### version (GET)
-
-```    
-curl -s http://localhost:5006/version
-```
-
-## More hints
+## Hints
 
 Canonicalization and prettifying:
 
-```bash
+```shell
 ./pretty_c14n.py before.xml after.xml
 ```
 
 Pretty printing the xml code:
 
-```bash    
+```shell
 cat foo.xml | tidy -xml --indent auto --indent-cdata yes --quiet yes \
   --wrap 0 --tab-size 2 - > bar.xml
 ```
 
+The /zz (GET) endpoint
+
+```shell
+curl -s http://localhost:5006/zz > zz.xml
+```
 
 
+returns a xml version based on the dummy certificate-document (`zz.json`)
+for test purpose.
 
+## TODO
 
+* update `zz.json`
+* allow json POST