The Services Directory can help you discover information about services available on a particular server. A service represents a local GIS resource whose functionality has been made available on the server to a wider audience. For example, an ArcGIS Server administrator can publish an ArcMap document (.mxd) as a map service. Developers and clients can display the map service and query its contents.
The Services Directory is available as part of the REST services infrastructure available with ArcGIS Server installations. It enables you to list the services available, including secured services when you provide a proper login. For each service, a set of general properties are displayed. For map services, these properties include the spatial extent, spatial reference (coordinate system) and supported operations. Layers are also listed, with links to details about layers, which includes layer fields and extent. The Services Directory can execute simple queries on layers.
The Services Directory is also useful for finding information about non-map service types. For example, you can use the Services Directory to determine the required address format for a geocode service, or the necessary model inputs for a geoprocessing service.
To open the Services Directory for an ArcGIS Server, you must know the URL of the server instance. In a typical installation of ArcGIS Server, the instance is installed in the web server's root directory as "arcgis". The Services Directory is in the "rest" folder inside the instance. For example, if the server is at www.example.com, the Services Directory would typically be at http://www.example.com/arcgis/rest/services. Contact the administrator of the ArcGIS Server system if you are uncertain about the server URL or ArcGIS instance.
You can get other useful information from the Services Directory beyond the service's URL. For example, to identify features within particular layers, you need to supply the IDs of the layers (see the walk-through Using QueryTask, Query, and FeatureSet). These IDs are listed with the Layers list in a map service's properties page in the Services Directory. If you need names of attribute fields to specify the information to return in a query, you can navigate to the layer's properties to find a list of fields.
Services and folders may be secured so that only authorized users may access them. If a service or folder does not appear as expected, it may require a login. If the server administrator has provided a username and password to you, click the Login link in the Services Directory and log in to see services permitted to you. For more information, see Working with secure ArcGIS services.
The ArcGIS Server REST API provides a relatively simple way to use services provided by ArcGIS Server. REST enables use of web resources by encapsulating information in the URL and query string of the request. It has become popular when combined with the technology known as AJAX for creating dynamic client-side web applications.