This chapter describes concepts used in all Web Service interfaces.
Each interface is described with a separate WSDL. The WSDL v1.1 specification distinguishes between two message styles: document and RPC. Furthermore there are different serialization formats, with SOAP encoding and literal being the two popular serialization formats today. The WSDLs shipped with Enterprise Server all use the document message style with literal encoding, also known as document/literal.
The Web Service interfaces use XML messages through an HTTP connection. Any files transferred are sent through SOAP attachments with DIME being used to encapsulate this into a single data stream. The SOAP message itself and the attachments are all encapsulated by DIME. To handle a DIME request or response, the DIME must be parsed to be able to access the SOAP message itself. There are only a few Web Services that transfer files, which is limited to the workflow- and planning interfaces. Those can be recognized by the dime:message element shown for the few operations in the WSDL, for example:
Note that the input element stands for the SOAP request fired by the client and the output element for the SOAP response returned by the server. The fragment above tells us that the CreateObjects operation (Web Service to upload documents) accepts DIME attachments, but that none are returned, which makes sense.
For more information on SOAP attachments, see here.
For more information on DIME encapsulation, see here.
Since Enterprise Server 8.0, it is recommended to use the Transfer Server instead of DIME. For both technologies, the DIME definitions in the WSDLs specify what service requests or responses can deal with file attachments.
A SOAP Fault is returned to clients when an error has occurred server-side during any Web Service execution. For example:
<faultstring>Access denied (S1002)</faultstring>
When the faultcode is set to Client it means that the caller has somehow passed wrong parameters or tries to do something that is against the rules. When set to Server it means that the server is not ‘willing’ to process the operation or has an internal error. It is a rough indication who might have caused the error: Client or Server. Typically used for debugging.
The faultstring is a localized string that can be directly shown to the user. The server error code is attached to this message in “(Sxxxx)” format. Clients that need to know what error occurred, should parse this error code, for example by taking the code 1002 in the given example. Clients sometimes know better what happened than the server, especially when firing many requests to establish one logical heavy operation. They are free to interpret the error code and display other messages (other than the ones returned to the client) to help the user understand what happened. The 1000-1999 range is reserved for operational errors; the 2000-2999 range is reserved for license errors.
Depending on the fault, a detail message can also be provided by the server to pass on extra information. The detail message is not localized and mostly cryptical, so it should never be shown to end users. In the given example, the server informs that the requested operation was performed for an object (ID=1661), for which the user has has no Change Status (C) access rights. Clients could try to parse this, but its format is free and subject to change. So, it is not recommended and should be used only in exceptional cases. For example, the server can add tokens as well to the detail message; for example in case an invalid ticket is passed (perhaps because it is expired) a fault is returned with detail message set to “SCEntError_InvalidTicket”. This should be checked by clients to determine if there is a need to raise the re-logon dialog.
Most Web Services require a ticket as input parameter. This ticket is obtained from the LogOn operation. The LogOn operation validates the user name and password and returns a ticket when the user account is valid. The ticket is used by clients for subsequent requests. Tickets are interchangeable between all interfaces.
By default, a logon/ticket session expires within 24 hours (or 1 hour for web clients). Whenever a request with a valid ticket arrives, the server resets its expiration timer for that session. As long as requests are fired before the expiration ends, clients are able to continue working, thereby keeping one license seat occupied. When a ticket has expired, an error is returned and the client needs to re-logon obtaining a new/different ticket. At this point, the clients risks that the last seat was taken in the meantime.
When the very same user does logon with the very same client application, but from a different location (IP address), the server assumes the user has moved. And so, the ticket from the first application is made invalid. This is to avoid accidentally keeping two license seats occupied for the whole day.
Cookie based tickets
Since Enterprise Server 10.2.0 it is possible to omit the ticket in the operation payload. When executing a LogOn operation the server will return the ticket as an cookie as well as in the content of the response. When the client has support for cookies (implemented a ‘cookie jar’), then the cookies are round tripped with every request to the server.
A cookie is set per AppName in the LogOn request. This allows multiple cookies to be set in the same cookie container for different clients. This occurs for example when you have multiple clients running in the same browser instance.
For the server to select the correct cookie it needs to know the AppName that is sending the request. A client can send this information by adding a special HTTP header to the request:
X-WoodWing-Application: <App Name as given in the LogOn response>
If the client can’t add the header for the request, a HTTP GET parameter can be added to the URL. This can occur for example when you want to load an image directly from the Transfer Server in an HTML img tag.
Note that this feature is just an addition to Enterprise Server. The ticket given in the request body will be supported side-by-side.
Unlike the stored information in the database, Enterprise Server itself is stateless. Every requested service runs on its own. When one service depends on another service, typically resulting data from one is passed on to the other. For example, an object id returned through a search query can be used to open the object file for editing.
Each service intends to represent one user operation. In other terms, when a user performs one action, there should be just one service executed only. This is needed for two reasons:
Performance - Think of a slow connection with one second network overhead. Performing five requests will require five seconds extra wait time, which is unacceptable.
Architecture - One service representing one logical action implies the need of passing all information to execute the service. This makes it possible to interpret the intention of the operation, which is why it is a good thing to develop custom solutions using Server Plug-ins hooking into Web Services.
However, in some cases multiple services are called by client applications, trigged by one logical action. For example, when a user logs in, Content Station typically requests to execute the inbox query immediately after, to show objects assigned to that user. Such scenarios are valid since running a query is a totally different logical operation than the login.
Client applications can wait for each service to complete and then fire a next request. This synchronous communication method works well but is far from optimal. Calling services asynchronously is allowed by Enterprise Server and can significantly speed up end user wait times. Content Station does this (by running multiple threads). Obviously, this can be done when there are no specific dependencies between services (as mentioned above).
One of the most often used structures in SOAP is the array. It allows transferring many of the same entities (objects,
relations, pages, etc.) in a list through requests and responses. The way arrays must be formatted is specified in the
WSDL. For Enterprise, those definitions are always prefixed with
ArrayOf followed by the entity name. For example:
<element name="Placement" minOccurs="0" maxOccurs="unbounded" type="tns:Placement"/>
It tells SOAP messages using this type that zero to many
Placement elements are allowed. The elements must be
structured as follows:
[Since 7.0] Since Enterprise Server 7.0 this notation has been changed to meet new standards with better support of SOAP tools. The definition has been changed in such a way that the old notation (usage) is still supported though:
<attribute ref="soap-enc:arrayType" wsdl:arrayType="tns:Placement"/>
This tells the same as before, but now a new notation can be used too:
<Placements SOAP-ENC:arrayType="ns1:Placement" xsi:type="SOAP-ENC:Array">
Basically, the parent
Placements attributes says that its child
item elements are actually
Content Station 7.x uses this technique, while Smart Connection 7.x for InDesign / InCopy still use the ‘old’ method.
User access rights
One of the keystones of the Enterprise workflow system is support for user access rights. Whenever an end user tries to do something for which no access is granted, and “Access denied (S1002)” error is raised. This should be determined by the server only and not by client applications. In such a case, the server returns a SOAP fault (see Errors). Such an error is shown in a dialog that is raised by client applications.
Enabling vs disabling access
Access rights are defined through Access Profiles. (See the Help Center for information about how to configure these.) Access feature options can be selected, which means they are enabled. However, when not selected, it does not(!) disable the feature; it only means that the feature is not enabled in this particular access profile, so you are not blocking access or something like that. A user has no access for a certain feature if there is no profile found with the corresponding option selected. For this reason, it is recommended to split options through many profiles and enable just a few. (This instead of having all enabled and disabling a few.) Else you might find yourself wondering why an end user has gained access unexpectedly.
Interpreting access definitions
When the end user performs a login action to the system, the server returns the configured profile definitions (through the LogOnResponse -> FeatureProfiles element) made by the admin user that are relevant for the end user. Only access options that have no default value are returned. You can determine the defaults by creating a new Access Profile through the admin pages and see which ones are selected. (At least up to Enterprise Server 7.0 all options are selected by default, with the exception of the “Force Track Changes” option.)
Let’s say that the system admin creates one Access Profile, clears the “Create Dossiers” option and names it “no Dossier creation”. The definition in the login response will look as follows:
<Name>no Dossier creation</Name>
Note that the “Create Dossiers” is a localized term. To uniquely identify this access feature, internal keys are used (in this case CreateDossier). Those keys can be used by client applications to look up and interpret. For example, a client application implementing a Create Dossier operation could check for this specific key.
With the definition available, the Brand admin can use it to give the end user access to the Brand in the Authorization Maintenance admin page. Let’s say that the Brand admin has given the end user access to the WW News Brand through the “no Dossier creation” profile (for all statuses and all Categories).
When the end user performs a login action, this configuration is reflected in the login response too (through Publications -> PublicationInfo -> FeatureAccessList element). See the figure below. The profile name (the text marked in red in the figure below) refers to the profile definition (the text marked in red in the figure above). This way clients can look up definitions. Because the Brand admin user has configured for all statuses and all Categories, respectively State and Section elements are not provided (xsi:nil attribute set to “true”). Nil typically means no specific item configured, which implies all options. (Note that Category was formerly named Section.) When configured, an id is filled in for those elements. When access rights are configured for an Issue with the “Overrule Brand” option enabled, the Issue element is used to pass its id. Note: the Overrule Brand option is no longer supported from Enterprise Server 10.7.0 onwards.
<Profile>no Dossier creation</Profile>
Changes since 10.7.0
Since Enterprise Server 10.7.0 the PublicationInfo and FeatureAccess list can also be requested via specific API calls. The WflGetPublications service can be used to get the PublicationInfo objects and the WflGetAuthorizations service can be used to get the FeatureProfile objects. For backwards compatibility the information is also returned in the LogOnResponse when explicitly requested in the RequestInfo.
Disabling GUI items
For user convenience, the client application GUI can be enhanced by hiding/disabling operations that are expected to always fail for a specific context. For example, when the user is not allowed to create Dossiers at all, no matter what, the client application could disable the “Create Dossier” operation in its GUI (such as context menus). Nevertheless, this must be done with great care. When disabling is done too rigidly it could accidentally withhold users from doing operations that they are allowed to. This can be implemented by interpreting the login response, specifically the two areas mentioned in the examples above. When the user is working in the context of the WW News Brand (for example selected in the GUI) the client needs to check all the profiles for that Brand (by looking up the profile definitions as explained above). If none of them gain access to the CreateDossier feature, it is safe to disable the “Create Dossier” operation in the GUI. If the context of the Brand is undetermined (for example global view on the system) all profiles (of all Brands) need to be checked. When the currently selected Issue (if any) has the Overrule Brand option set, only the configurations made for the Issue should be checked (and the configurations for its Brand should be ignored!).
Overruling access rights
When normal configurations made through admin pages do not fulfill the customer’s needs, Server Plug-ins could be the answer. Its connectors allow you to hook into any workflow service. See the Server Plug-ins documentation for more info. When any operation is not allowed, the connector could throw a BizException as follows:
throw new BizException( 'ERR_AUTHORIZATION', 'Server', '' );
For example, it could check if the end user is member of a specific user group, it could check the status of the object involved, it could check the deadline and system time, etc, and then decide to block access.