--- /dev/null
+# feature definition
+
+A feature represents a location. It has index _fid_. It has two dimensions:
+_lagitude_ and _longitude_. It may have an image represented by it's url.
+This field is called _imgurl_; it may also have a _title_ and/or a _description_.
+
+# client to server communication:
+
+Client submits a classic html form to server.
+
+**note**: In this documentation, php notation is used (`_POST` and `_FILES`),
+but server may be written in any language.
+
+`_POST["request"]` is either:
+
+## auth
+ asks for authentication
+
+ * ` _POST["password"]` must contains user password
+
+## add
+ adds a new feature
+
+ * `_POST["lon"]` must contain feature longitude
+ * `_POST["lat"]` must contain feature latitude
+ * `_POST["title"]` may contain feature title
+ * `_POST["description"]` may contain feature description
+ * `_FILES["image_file"]` may contain an uploaded image
+
+## del
+ to delete an existing feature
+
+ * `_POST["fid"]` must contain feature id
+
+## update
+ to modify an existing feature
+
+ * `_POST["fid"]` must contain feature id
+ * `_POST["lon"]` must contain feature longitude
+ * `_POST["lat"]` must contain feature latitude
+ * `_POST["title"]` may contain feature title
+ * `_POST["description"]` may contain feature description
+
+ if `_POST["keep_img"]` is "yes", feature image will not be modified.
+ Otherwise, `_FILES["photo_file"]` is checked for an uploaded file. If
+ `_FILES["photo_file"]` is empty, existing feature image will be deleted.
+ Otherwise, uploaded file will replace current feature image.
+
+# server reply to client:
+Server replies with xml content. In an ideal world, reply would be just xml
+content. But due to technical issues, syp must wrap xml content in the body of a
+html document. So for example, instead of sending
+
+`<error reason="unauthorized"></error>`
+
+as _text/xml_, syp sends
+
+`<html><head></head><body><error reason="unauthorized"></error></body></html>`
+
+as _text/html_
+
+## error handling:
+
+ reply is something like `<error reason="?reason?"></error>` with _?reason?_ can be either:
+
+ * `unauthorized`: user is not authorized to execute request, or authentication failed
+ * `server`: an error occured on server side (such as database problem)
+ * `request`: server could not understand request
+ * `toobig`: uploaded file was too big
+ * `notation`: uploaded file was not an image
+ * `nochange`: when trying to update a feature, there is nothing to update (ie: no field of the feature has changed)
+
+## success handling:
+
+ * `<success request="auth"></success>`:
+ authentication was successfull
+
+ * `<success request="del">
+ <feature>
+ <id>?id?</id>
+ </feature>
+ </success>`:
+ deletion was successfull. _?id?_ was property of deleted feature
+
+* `<success request="add">
+ <feature>
+ <id>?id?</id>
+ <imgurl>?imgurl?</imgurl>
+ <description>?description?</description>
+ <heading>?heading?</heading>
+ <lon>?lon?</lon>
+ <lat>?lat?</lat>
+ </feature>
+ </success>`:
+ addition was successfull. _?id?_, _?imgurl?_, _?description?_,
+ _?heading?_, _?lon?_, _?lat?_ are properties of added feature;
+
+* `<success request="update">
+ <feature>
+ <id>?id?</id>
+ <imgurl>?imgurl?</imgurl>
+ <description>?description?</description>
+ <heading>?heading?</heading>
+ <lon>?lon?</lon>
+ <lat>?lat?</lat>
+ </feature>
+ </success>`:
+ update was successfull. _?id?_, _?imgurl?_, _?description?_, _?heading?_,
+ _?lon?_, _?lat?_ are properties of updated feature;
projects / syp.git / blobdiff