Class SetTemplate

java.lang.Object
sunlabs.brazil.template.Template
sunlabs.brazil.template.SetTemplate
All Implemented Interfaces:
Serializable, Handler, TemplateInterface
Direct Known Subclasses:
MultipartSetTemplate

public class SetTemplate extends Template implements Serializable, Handler
Template (and handler) class for setting and getting values to and from the current (or other) request context. This class is used by the TemplateHandler. The following tags are processed by this class:
  • <set name=.. [value=..] [namespace=..]>
  • <get name=.. [default=..] [namespace=..] [max=nnn] [convert=html|url|none] [set=..]>
  • <namespace name=.. [clear] [remove] [store=xxx] [load=xxx]>
  • <import namespace=.. />
  • <unimport namespace=.. />
  • <tag [name=..]>
  • </tag>

The tag<set> is processed with the following attributes:

name=value
The name of the entry to set in the request properties.
value=value
The value to store in the property. If this option is not specified, then the existing value for this property will be removed.
default=other
If default is specified and the specified value was the empty string "", then store this other value in the property instead. other is only evaluated in this case.
local
By default, variables are set (or removed from) a namespace that is persistent across all requests for the same session. If local is specified, the values only remain for the duration of the current request. [Deprecated - use namespace=local]
namespace
The namespace to use to set or delete the property. The default is namespace=${SessionID}, unless set is inside the scope of an enclosing namespace tag. Namespaces are used to define variable scopes that may be managed explicitly in template pages.

Two namespaces are treated specially:

  • local
    may be used to set (or clear) values from request.props.
  • server
    may be used to set (or clear) values from server.props, unless "noserver" is defined in which case hte "Server" namespace is not treated specially.

The <namespace>..</namespace> tag pairs are used to specify a default namespace other than the SessionId for the set and import tags or manipulate a namespace. When a namespace is in effect, the request property [prefix].namespace is set to the current namespace, where [prefix] is the RewriteContext.templatePrefix. This permits other templates (such as the ListTemplate) to use the current namespace setting. These tags don't nest.

attributes for namespace:

name=value
The default namespace to use for the set and import default namespace name.
clear
If set, namespace name is cleared.
remove
If set, namespace name is removed.
load=file_name
If specified, and the property saveOk is set, then the specified namespace will be saved loaded from a file in java properties format. Relative path names are resolved with respect to the document root.
store=file_name
If specified, and the property saveOk is set, then the specified namespace will be stored to a file in java properties format. Relative path names are resolved with respect to the document root.
When using load or store, the namespace names "local" and "server" are treated specially, referring to "request.props" and "server.props" respectively.

The tag<import> (and <unimport>) are processed with the following attributes:

namespace=value
The name/value pairs assiciated with the namespace are made available for the remainder of the page.

The "unimport" taq should probably be replaced by <import>

The "get" (formerly property) tag has the following attributes:

name
The name of the variable to get
namespace
The namespace to look in. By default, the variable is searched for in "request.props"
default
The value to use if no value matches "name".
convert
The conversion to perform on the value of the data before substitution: "html", "url", "lower, "trim", or "none" (the default). For "html", any special html syntax is escaped. For "url", the data will be suitable for transmission as an http URL. The "lower" and "trim" options convert to lowercase and remove leading and trailing whitespace, respectively.
max
The output is truncated to at most max characters.
If a single attribute is specified, with no "=", then is is taken to be the "name" parameter. Thus: <get foo> is equivalent to: <get name="foo">.

Request Properties:

sessionTable
The name of the SessionManager table to use for storing values. Defaults to the template handler's prefix. When configured in one server both as a handler and a template, the sessionTable should be set to the same value in both cases to get a useful result.
debug
If set, the original tag is included in a comment, otherwise it is removed entirely.
mustMatch
Set to a glob pattern that all names must match in order to be set. This may be used to prevent malicious html pages (what a concept) from changing inappropriate values.
noserver
The "server" namespace will no longer be mapped to server.props
noSet
If set, then the "set" tag will be disabled.
querySet
If set, then properties may be set in query parameters, to the "handler" portion, but only if they match the glob pattern.
autoImport
If set to "1", the namespace for the session is automatically imported. (defaults to "1");
imports
Defines a set of (white space delimited) namespaces that will automatically be imported at the beginning of each page. Each namespace name will be processed for ${...} substitutions before an import is attempted. If the namespace doesn't already exist, the import is ignored.
query
The query parameters are inserted into the request object, prefixed by the value assigned to "query".
headers
The mime headers are inserted into the request object, prefixed by the value assigned to "headers".

In addition, the following properties (prefixed with "headers") are also set:

  • address The ip address of the client
  • counter A monotonically increasing counter (# of client requests accepted since the server started).
  • method The request method (typically GET or POST).
  • protocol The client HTTP protocol level (for 1.0 or 1.1)
  • query The current query data, if any.
  • timestamp A timestamp (in ms since epoch) from when this request was first accepted.
  • url The current url.
  • hostname, hostport The name and port parts of the "host" header, if set.
url.orig
If set and "headers" are requested, this value is used as the url instead of the one in request.url.

Normally, any persistent properties held by the SetTemplate are chained onto the request.props when the init method is found. If this template is installed as an up-stream handler, then the persistent properties associated with the session are made available at that time.

When used as a handler, the following property is used:

session=value
The request property to find the session information in. Normally this should be the same as the session property used by the container calling this as a template.
saveOk
This must be specified in order for the "namespace store" or "namespace load" functions to operate.
Version:
@(#)SetTemplate.java 2.15
Author:
Stephen Uhler
See Also:
  • Constructor Details

    • SetTemplate

      public SetTemplate()
  • Method Details

    • init

      public boolean init(RewriteContext hr)
      Chain the session-id properties into the request chain, if there are any. If "query" or "headers" are requested for "get", then add in those properties to request.props.
      Specified by:
      init in interface TemplateInterface
      Overrides:
      init in class Template
    • tag_set

      public void tag_set(RewriteContext hr)
      Set the value of a variable. Allow variable substitutions in the name and value. Don't create property tables needlessly.

      Attributes:

      name
      The name of the variable to set
      value
      The value to set if to.
      namespace
      The namespace to look in. By default, the variable is set in the namespace associated with the current "SessionId".
      local
      A (deprecated) alias for "namespace=local", or the current request.props.
    • tag_property

      public void tag_property(RewriteContext hr)
      Convert the html tag "property" in to the request's property DEPRECATED - use "get"
    • tag_get

      public void tag_get(RewriteContext hr)
      Replace the tag "get" with the value of the variable specified by the "name" attribute.

      Attributes:

      name
      The name of the variable to get
      namespace
      The namespace to look in. By default, the variable is searched for in "request.props". The namespace "server" is used to look in the server's namespace. The namespace "local" is a synonym for the default namespace.
      default
      The value to use if no value matches "name".
      convert
      The conversion to perform on the value of the data before substitution: "html", "url", or "none" (the default). For "html", any special html syntax is escaped. For "url", the data will be suitable for transmission as an http URL.
      max
      Truncate the String to at most max characters. Max must be at least one, and truncation occurs after any conversions.
      set
      The resultant value is placed into the request property named by the set attribute, and not inserted into the HTML stream. If none of "namespace", "convert", or "match" is used, then this simply copies the property from one name to another.
      If a single attribute is specified, with no "=", then is is taken to be the "name" parameter. Thus: <get foo> is equivalent to: <get name="foo">.
    • tag_import

      public void tag_import(RewriteContext hr)
      Import all the data from the named namespace. The namespace associated with the session ID is imported automatically for backward compatibility. If the namespace doesn't exist, don't create it now, but remember it needs to be "Chained" if it is created on this page.
    • tag_unimport

      public void tag_unimport(RewriteContext hr)
      Un-import a previously imported namespace.
    • tag_namespace

      public void tag_namespace(RewriteContext hr)
      Set the default namespace for "set" and "import".
    • file2path

      public File file2path(Properties p, String prefix, String name)
      Convert a file name into a file object. relative paths use are resolved relative to the document root
      Parameters:
      p - properties file to find the doc root in
      prefix - the properties prefix for root
      name - the name of the file
    • tag_slash_namespace

      public void tag_slash_namespace(RewriteContext hr)
      Clear the default namespace for "set" and "import".
    • tag_tag

      public void tag_tag(RewriteContext hr)
      Insert a literal "<". Using the current scheme, there is no easy way to substitute into a tag parameter. So we'll invent a "magic" tag (called tag) that will allow us to create entities dynamically. Thus values can be substituted into entities by escaping the entity as in:
       <tag>a href=<property href></tag>
       

      The [optional] attribute "name" may be used to specify the name of the tag, which will be emmitted just after the "<".

    • tag_slash_tag

      public void tag_slash_tag(RewriteContext hr)
      Insert a literal ">"
    • init

      public boolean init(Server server, String prefix)
      Get the 2 SessionManager keys, "sessionTable" and "session" (SessionID).
      Specified by:
      init in interface Handler
      Parameters:
      server - The HTTP server that created this Handler. Typical Handlers will use Server.props to obtain run-time configuration information.
      prefix - The handlers name. The string this Handler may prepend to all of the keys that it uses to extract configuration information from Server.props. This is set (by the Server and ChainHandler) to help avoid configuration parameter namespace collisions.
      Returns:
      true if this Handler initialized successfully, false otherwise. If false is returned, this Handler should not be used.
    • respond

      public boolean respond(Request request)
      Chain a SessionManager entries onto the request properties, and optionally allow setting of request props from query parameters. Only the session id table can be chained, and values (if any) are set in request.props (i.e. namespace=local)
      Specified by:
      respond in interface Handler
      Parameters:
      request - The Request object that represents the HTTP request.
      Returns:
      true if the request was handled. A request was handled if a response was supplied to the client, typically by calling Request.sendResponse() or Request.sendError.
    • doImport

      public boolean doImport(RewriteContext hr)
      See if a remembered namespace is actually in use, and import it. (This is a workaround). If some other template causes a namespace that was previously imported but empty to be created, then this tells us that it is now populated, and should be added to the chain. [a better implementation might have us register interest in a namespace, so we would be called automatically upon creation, instead of requiring the creator to know about us and make this call explicitly.]