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DO NOT EDIT THE CONTENT OF THIS PAGE DIRECTLY, UNLESS YOU KNOW WHAT YOU'RE DOING.
THE STRUCTURE OF THE CONTENT IS VITAL IN BEING ABLE TO EXTRACT CHANGES FROM THE PAGE AND MERGE THEM BACK INTO SERVOY SOURCE{hidden}
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Using
...
the
...
RESTful
...
Web
...
Service
...
plugin
...
business
...
logic
...
can
...
be
...
exposed
...
as
...
a
...
RESTful
...
Web
...
Service.
...
About RESTful Web Services
RESTful Web Services utilize the features of the HTTP Protocol to provide the API of the Web Service. For example, it used the HTTP Request Types to indicate the type of operation:
Operation | HTTP Request Type |
|---|---|
Retrieving of existing records | GET |
Creating new records | POST |
Removing records | DELETE |
Updating existing records | PUT |
Using these 4 HTTP Request Types a RESTful API mimics the CRUD operations (Create, Read, Update & Delete) common in transactional systems.
A defining feature of REST is that it is stateless: each call the to a RESTful Web Service is completely stand-alone: it has no knowledge of previous requests.
Implementing a RESTful Web Service in Servoy
The RESTful Web Service plugin does not contain any client side functions or properties, it is a 100% server side operating plugin.
A RESTful Web Service can be created by creating a Form in a solution and implement one or more of the following methods to the Form:
Method name | HTTP Request Type | Description |
|---|---|---|
ws_read | GET | Used for the retrieval of data |
ws_create | POST | Used for the creation of new records |
ws_delete | DELETE | Used for the removal of data |
ws_update | PUT | Used for updating data |
ws_authenticate | N/A | Used to authenticate the requesting client |
ws_response_headers | N/A | Allows the retrieval in the HTTP Headers in the incoming Request and set the HTTP headers in the outgoing Response |
Implement ws_read():Object to allow data retrieval
By performing an HTTP GET on the url {serverUrl}/servoy-service/rest_ws/
...
{solutionName}/
...
{formName},
...
the
...
ws_read()
...
method
...
will
...
be
...
invoked.
...
The
...
method
...
must
...
return
...
a
...
JavaScript
...
object.
...
The
...
object
...
will
...
be
...
serialized
...
and
...
placed
...
in
...
the
...
body
...
of
...
the
...
HTTP
...
Response.
...
If
...
the
...
return
...
value
...
of
...
the
...
method
...
is
...
null,
...
a
...
NOT_FOUND
...
response
...
(HTTP
...
404)
...
will
...
be
...
generated
Implement ws_create(content):Object
...
to
...
allow
...
adding
...
data
...
By
...
performing
...
an
...
HTTP
...
POST
...
on
...
the
...
url
...
{serverUrl}/servoy-service/rest_ws/
...
{solutionName}/
...
{formName},
...
the
...
ws_create()
...
method
...
will
...
be
...
invoked.
...
Data
...
has
...
to
...
be
...
supplied
...
in
...
the
...
body
...
of
...
the
...
HTTP
...
Request.
...
The
...
method
...
can
...
return
...
a
...
JavaScript
...
object.
...
The
...
object
...
will
...
be
...
serialized
...
and
...
placed
...
in
...
the
...
body
...
of
...
the
...
HTTP
...
Response.
...
Implement ws_delete():Boolean
...
to
...
allow
...
data
...
removal
...
By
...
performing
...
an
...
HTTP
...
DELETE
...
on
...
the
...
url
...
{serverUrl}/servoy-service/rest_ws/
...
{solutionName}/
...
{formName},
...
the
...
ws_delete()
...
method
...
will
...
be
...
invoked.
...
The
...
method
...
has
...
to
...
return
...
a
...
Boolean
...
value:
...
– true:
...
to
...
indicate
...
successful
...
deletion.
...
This
...
result
...
will
...
generate
...
an
...
OK
...
response
...
(HTTP
...
200)
...
– false:
...
to
...
indicate
...
delete
...
failure.
...
This
...
response
...
will
...
generate
...
a
...
NOT_FOUND
...
response
...
(HTTP
...
404)
...
Implement ws_update(content):Boolean
...
to
...
allow
...
updating
...
existing
...
data
...
By
...
performing
...
an
...
HTTP
...
PUT
...
on
...
the
...
url
...
{serverUrl}/servoy-service/rest_ws/
...
{solutionName}/
...
{formName},
...
the
...
ws_update()
...
method
...
will
...
be
...
invoked.
...
Data
...
has
...
to
...
be
...
supplied
...
in
...
the
...
body
...
of
...
the
...
HTTP
...
request.
...
The
...
method
...
has
...
to
...
return
...
a
...
Boolean
...
value:
...
– true:
...
to
...
indicate
...
successful
...
update.
...
This
...
result
...
will
...
generate
...
an
...
OK
...
response
...
(HTTP
...
200)
...
– false:
...
to
...
indicate
...
update
...
failure.
...
This
...
response
...
will
...
generate
...
a
...
NOT_FOUND
...
response
...
(HTTP
...
404)
...
In case the matching method for the specific HTTP operation (GET,
...
POST,
...
DELETE
...
or
...
PUT)
...
does
...
not
...
exists
...
on
...
the
...
form,
...
an
...
INTERNAL_SERVER_ERROR
...
response
...
(HTTP
...
500)
...
will
...
be
...
generated.
...
Request
...
parameters
...
Additional
...
parameters
...
can
...
be
...
specified
...
in
...
the
...
URL
...
of
...
the
...
HTTP
...
Requests.
...
There
...
are
...
two
...
variations
...
and
...
how
...
they
...
are
...
forwarded
...
to
...
the
...
ws_*
...
methods
...
differs.
...
Additional
...
URL
...
path
...
elements
...
The
...
base
...
URL
...
for
...
each
...
operation
...
is
...
{serverUrl}/servoy-service/rest_ws/
...
{solutionName}/
...
{formName}.
...
Additional
...
arguments
...
can
...
be
...
specified
...
by
...
adding
...
to
...
the
...
URL
...
path:
...
| Code Block |
|---|
{serverUrl}/servoy-service/rest_ws/{solutionName}/{formName}/{someValue}/{anotherValue}
{code}
|
The
...
additional
...
URL
...
path
...
elements
...
{someValue}
...
and
...
{anotherValue}
...
will
...
be
...
passed
...
into
...
the
...
ws_*
...
method
...
as
...
additional
...
arguments.
...
This
...
means
...
that
...
for
...
ws_read()
...
and
...
ws_delete()
...
they
...
will
...
be
...
the
...
first
...
and
...
second
...
argument
...
and
...
for
...
ws_create()
...
and
...
ws_update()
...
they
...
will
...
be
...
the
...
2nd
...
and
...
3rd
...
argument,
...
as
...
these
...
method
...
already
...
have
...
by
...
default
...
the
...
content
...
of
...
the
...
request
...
as
...
first
...
argument
...
Query
...
parameters
...
The
...
request
...
URLs
...
can
...
also
...
be
...
extended
...
with
...
Query
...
parameters:
...
{serverUrl}/servoy-service/rest_ws/
...
{solutionName}/
...
{formName}?
...
{someKey}=
...
{someValue}&
...
{anotherKey}=
...
{anotherValue}&&
...
{anotherKey}=
...
{anotherValue2}
...
If
...
the
...
URL
...
contains
...
Query
...
parameters,
...
these
...
will
...
be
...
passed
...
into
...
the
...
ws_*
...
method
...
as
...
an
...
additional
...
last
...
argument.
...
This
...
last
...
argument
...
is
...
a
...
JavaScript
...
object
...
containing
...
all
...
keys
...
as
...
properties
...
with
...
the
...
values
...
associated
...
with
...
the
...
key
...
in
...
a
...
Array:
...
Object<Array<String>>
...
Example
Additional URL path elements and Query parameters can be combined in the URL (the query parameters should come after the additional URL path elements):
| Code Block |
|---|
{serverUrl}/servoy-service/rest_ws/{solutionName}/{formName}/{someValue}/{anotherValue}?{someKey}={someValue}&{anotherKey}={anotherValue}&&{anotherKey}={anotherValue2}{code}
|
A
...
HTTP
...
Get
...
Request
...
on
...
url
...
{serverUrl}/servoy-service/rest_ws/myRestAPISolution/APIv1/foo/bar?name=John&age=30&pet=Cat&pet=Dog
...
would
...
result
...
in
...
invoking
...
the
...
ws_read
...
method
...
on
...
form
...
'APIv1'
...
of
...
solution
...
'myRestAPISolution'.
...
The
...
ws_read
...
function
...
will
...
be
...
invoked
...
with
...
three
...
parameters:
...
'foo',
...
'bar',
...
{name:
...
...
,
...
age:
...
...
,
...
pet:
...
...
...
}
...
| Code Block |
|---|
function ws_read()
{
for (var i = 0; arguments.length, i++) {
if (typeof arguments[i] == 'String') { //The URL path additions are passed in as Strings
application.output('URL Path addition: ' + arguments[i])
} else {
for each (var key in arguments[i]) {
application.output('Query Parameter "' + key + '", values: "' + arguments[i][key].join(', ') + '"')
}
}
}
}
//outputs:
//URL Path addition: foo
//URL Path addition: bar
//Query Parameter "name", values: "John"
//Query Parameter "age", values: "30"
//Query Parameter "pet", values: "Cat, dog"
{code}
h4.Stateless
RESTful Web Services are to be stateless. As subsequent requests to the RESTful Web Service API might be handled by different headless clients in the pool of clients configured for the plugin, do not use any state in between calls to the API. This means at least the following:
- Do not use global or form variables
- Do not use the solution model API
- Do not alter the state of the a form's UI
- Do save or rollback any unsaved changes before the end of the method
h4.HTTP Request
For the POST and PUT operation (resp. ws_create() and ws_update() methods), data has to be supplied in the body of the HTTP Request. If the content in the body of the HTTP Request is missing, a NO_CONTENT response will be generates (HTTP 204).
The supported Content-Types are JSON (application/json) and XML (application/xml). The Content-Type can be explicitly set in the header of the HTTP Request:
{code} |
Stateless
RESTful Web Services are to be stateless. As subsequent requests to the RESTful Web Service API might be handled by different headless clients in the pool of clients configured for the plugin, do not use any state in between calls to the API. This means at least the following:
- Do not use global or form variables
- Do not use the solution model API
- Do not alter the state of the a form's UI
- Do save or rollback any unsaved changes before the end of the method
HTTP Request
For the POST and PUT operation (resp. ws_create() and ws_update() methods), data has to be supplied in the body of the HTTP Request. If the content in the body of the HTTP Request is missing, a NO_CONTENT response will be generates (HTTP 204).
The supported Content-Types are JSON (application/json) and XML (application/xml). The Content-Type can be explicitly set in the header of the HTTP Request:
| Code Block |
|---|
Content-Type: application/json; charset=utf-8{code}
{code} |
| Code Block |
|---|
Content-Type: application/xml; charset=utf-8{code}
|
Note:
...
the
...
charset
...
is
...
optional.
...
If
...
not
...
specified,
...
utf-8
...
will
...
be
...
assumed.
...
If
...
no
...
valid
...
Content-Type
...
is
...
set,
...
the
...
plugin
...
will
...
try
...
to
...
establish
...
the
...
type
...
of
...
the
...
content
...
based
...
on
...
the
...
first
...
character
...
of
...
the
...
content:
...
- '
...
- {':
...
- Content-Type
...
- application/json
...
- will
...
- be
...
- assumed
...
- '<':
...
- Content-Type
...
- application/xml
...
- will
...
- be
...
- assumed
...
When
...
the
...
Content-Type
...
cannot
...
be
...
determined,
...
an
...
UNSUPPORTED_MEDIA_TYPE
...
response
...
will
...
be
...
generated
...
(HTTP
...
415).
...
The
...
supplied
...
value
...
in
...
the
...
body
...
of
...
the
...
HTTP
...
request
...
will
...
be
...
applied
...
as
...
argument
...
to
...
the
...
invocation
...
of
...
the
...
method.
...
The
...
body
...
content
...
will
...
be
...
converted
...
to
...
a
...
JavaScript
...
object
...
automatically.
...
If
...
the
...
body
...
content
...
cannot
...
be
...
converted
...
to
...
a
...
JavaScript
...
object
...
based
...
on
...
the
...
Content-Type
...
an
...
INTERNAL_SERVER_ERROR
...
response
...
(HTTP
...
500)
...
will
...
be
...
generated.
...
HTTP
...
Response
...
By
...
default,
...
the
...
plugin
...
will
...
respond
...
with
...
the
...
same
...
Content
...
Type
...
as
...
was
...
specified
...
in
...
the
...
HTTP
...
Request.
...
This
...
can
...
be
...
overruled
...
by
...
specifying
...
a
...
different
...
response
...
Content-Type
...
in
...
the
...
Accept
...
header
...
of
...
the
...
HTTP
...
Request:
...
| Code Block |
|---|
Accept: application/json{code}
|
By
...
default,
...
the
...
response
...
will
...
be
...
encoded
...
with
...
the
...
UTF-8
...
charset.
...
If
...
the
...
HTTP
...
Request
...
specified
...
a
...
different
...
encoding,
...
that
...
will
...
be
...
used
...
instead.
...
If
...
the
...
encoding
...
of
...
the
...
response
...
needs
...
to
...
be
...
different
...
than
...
the
...
request
...
encoding,
...
this
...
can
...
be
...
specified
...
in
...
the
...
HTTP
...
Request
...
by
...
setting
...
the
...
charset
...
value
...
in
...
the
...
Accept
...
header:
...
| Code Block |
|---|
Accept: application/json; charset=UTF-16{code}
h4. Returning custom status codes
While some of the HTTP Response status codes are hardcoded in the RESTful Webservices plugin (see this documentation), it is possible to control the HTTP Status codes from within the ws_* methods. Returning a custom HTTP Status Code can be done by throwing the specific value (a number) for the HTTP Status Code.
For example, when a ws_update call comes in for a non-existing resource, the HTTP Status Code to return would be a "Not Found" status code, which is a 404. Returning the 404/Not Found HTTP Status code from within a ws_* method could be done the following way:
{code} |
Returning custom status codes
While some of the HTTP Response status codes are hardcoded in the RESTful Webservices plugin (see this documentation), it is possible to control the HTTP Status codes from within the ws_* methods. Returning a custom HTTP Status Code can be done by throwing the specific value (a number) for the HTTP Status Code.
For example, when a ws_update call comes in for a non-existing resource, the HTTP Status Code to return would be a "Not Found" status code, which is a 404. Returning the 404/Not Found HTTP Status code from within a ws_* method could be done the following way:
| Code Block |
|---|
function ws_update(){
//your logic here
throw 404;
}
{code}
|
For
...
convenience
...
purposes,
...
all
...
available
...
HTTP
...
Status
...
Codes
...
are
...
also
...
listed
...
under
...
the
...
...
...
shipped
...
with
...
Servoy,
...
so
...
instead
...
of
...
throwing
...
the
...
number
...
404
...
in
...
the
...
previous
...
example,
...
a
...
more
...
readable
...
way
...
would
...
be
...
to
...
throw
...
plugins.http.HTTP_STATUS.SC_NOT_FOUND
...
See
...
...
on WikipediA for additional information on all status codes
Authentication/Authorization
The RESTful Web service plugin can be configured to check authentication/authorisation.
The plugins server property rest_ws_plugin_authorized_groups
...
can
...
be
...
set
...
with
...
a
...
comma
...
separated
...
list
...
of
...
groups
...
defined
...
in
...
the
...
built-in
...
security
...
system
...
of
...
Servoy.
...
When
...
the
...
property
...
is
...
filled
...
with
...
usergroups,
...
HTTP
...
Basic
...
authentication
...
is
...
enabled
...
for
...
all
...
webservice
...
requests.
...
The
...
username/password
...
supplied
...
in
...
the
...
HTTP
...
Request
...
is
...
validated
...
against
...
the
...
users
...
registered
...
in
...
Servoy's
...
built-in
...
security
...
system
...
and
...
additionally
...
against
...
group
...
membership.
...
Access
...
is
...
denied
...
if
...
the
...
user
...
does
...
not
...
exists
...
or
...
the
...
supplied
...
password
...
is
...
incorrect,
...
or
...
the
...
user
...
doesn't
...
belong
...
to
...
one
...
of
...
the
...
specified
...
groups.
...
When
...
access
...
is
...
denied,
...
an
...
UNAUTHORIZED
...
response
...
is
...
generated
...
(HTTP
...
401).
...
JSONP
...
support
...
The
...
plugin
...
supports
...
so-called
...
JSONP:
...
a
...
variation
...
of
...
JSON
...
that
...
allows
...
cross
...
domain
...
data
...
retrieval.
...
The
...
JSONP
...
variation
...
can
...
be
...
invoked
...
by
...
added
...
a
...
"callback"
...
parameter
...
to
...
the
...
HTTP
...
Request
...
URL:
...
| Code Block |
|---|
http://domain:port/servoy-service/rest_ws/\{solutionName}/\{formName}?callback=\{callbackFunctionName}
{code}
|
When
...
invoked
...
with
...
the
...
value
...
"myCallback"
...
for
...
the
...
"callback"
...
parameter,
...
the
...
returned
...
JSON
...
value
...
will
...
be
...
wrapped
...
in
...
a
...
function
...
call
...
to
...
the
...
"myCallback"
...
function:
...
| Code Block |
|---|
myCallback({ "hello" : "Hi, I'm JSON. Who are you?"})
{code}
h4.Pool of Clients
To service the requests to the RESTful Web service API, the plugin creates a pool of (headless) clients. The maximum number of clients allowed can be set using the |
Pool of Clients
To service the requests to the RESTful Web service API, the plugin creates a pool of (headless) clients. The maximum number of clients allowed can be set using the "rest_ws_plugin_client_pool_size"
...
property
...
of
...
the
...
plugin
...
(default
...
value
...
=
...
5).
...
When
...
there
...
are
...
more
...
concurrent
...
requests
...
than
...
the
...
number
...
of
...
clients
...
in
...
the
...
pool,
...
by
...
default
...
the
...
requests
...
will
...
wait
...
until
...
a
...
client
...
becomes
...
available
...
in
...
the
...
pool.
...
This
...
behavior
...
can
...
be
...
altered
...
by
...
setting
...
the
...
"rest_ws_plugin_client_pool_exhausted_action"
...
property
...
of
...
the
...
plugin.
...
The
...
following
...
values
...
are
...
supported
...
for
...
this
...
property:
...
- block
...
- (default):
...
- requests
...
- will
...
- wait
...
- untill
...
- a
...
- client
...
- becomes
...
- available
...
- fail:
...
- the
...
- request
...
- will
...
- fail.
...
- The
...
- API
...
- will
...
- generate
...
- a
...
- SERVICE_UNAVAILABLE
...
- response
...
- (HTTP
...
- 503)
...
- grow:
...
- allows
...
- the
...
- pool
...
- to
...
- temporarily
...
- grow,
...
- by
...
- starting
...
- additional
...
- clients.
...
- These
...
- will
...
- be
...
- automatically
...
- removed
...
- when
...
- not
...
- required
...
- anymore.
...
| Note | ||||||||
|---|---|---|---|---|---|---|---|---|
| =
|
| }||||||
The RESTful Web service plugin uses a pool of headless clients to service the requests. When operated within a Servoy Cluster, note that poolsize is set per Servoy Application Server. {note} h4.Samples A sample solution is included in the Servoy distribution |
Samples
A sample solution is included in the Servoy distribution (servoy_sample_rest_ws.servoy),
...
detailing
...
how
...
to
...
retrieve
...
data
...
from
...
the
...
http
...
request
...
and
...
to
...
return
...
a
...
response.
...
For
...
more
...
information
...
on
...
RESTful
...
Web
...
Services,
...
see:
...
http://en.wikipedia.org/wiki/Representational_State_Transfer
...
http://www.infoq.com/articles/rest-introduction
...
http://www.ibm.com/developerworks/webservices/library/ws-restful/
...
http://home.ccil.org/~cowan/restws.pdf
...
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