README update (SODA pure config and run)

README.md

@@ -3,7 +3,7 @@
 is a web-application to access astronomical data stored in FITS-files.
 It implements SODA IVOA recommendation v1.0 (https://ivoa.net/documents/SODA/20170517/index.html).
 
-Docker image is available in this repository and cean be launched by the following compose.yaml
+Docker image is available in this repository and may be launched by the following **compose.yaml**.
 
 ```yaml
 version: '3' 
@@ -21,20 +21,29 @@ services:
       - /srv/ska/surveys:/srv/surveys:z,ro
     restart: always
 
+```
 
-  soda-ssl:
-    container_name: soda-ssl-vlkb
-    image: git.ia2.inaf.it:5050/vialactea/vlkb-soda/soda:1.6.3
-    ports:
-      - 18025:8443
-    environment:
-      - SECURITY=ia2token
-      - ACCESS_CONTEXT_ROOT=ska#datasets
-    volumes:
-      - /srv/ska/surveys:/srv/surveys:z,ro
-    restart: always
+The above configuaration assumes:
+
+* 'SKA' project holds FITS-files in sub-directories under: `/srv/ska/surveys`
+* will be accessed remotely by URL: http://<server>/ska/datasets/soda
+* identified by SODA-param ID which is **IVOID** of the form:
+`ID=ivo://<authority>/resource-key?<relative-pathname>#extnum`
+
+Note that the service apends **soda** to ACCESS_CONTEXT_ROOT.
+The pathname in the ID is relative to the path in compose.yaml volume-mapping (e.g. '/srv/ska/surveys').
+The FITS extension number `#extnum` is optional. Default is the primary HDU.
+
+Data access example:
+```bash
+curl -s -k --get
+    --data-urlencode "ID=ivo://some-auth/some-key?some/path/somefile.fits"
+    --data-urlencode "CIRCLE=202.256 47.493 0.2"
+    -v -o soda.fits
+    http://localhost:18019/ska/datasets/soda
 ```
 
+The URL root `http://localhost:18019/ska/datasets/soda` returns the service descriptor.
 
 ## SODA for VLKB