RENDER.GETBLOBURL

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RENDER.GETBLOBURL

Creates a BlobServer URL without embedding it in an HTML tag.

Syntax

<RENDER.GETBLOBURL
      OUTSTR="VariableName"
      [BLOBTABLE="blobTable"]
      [BLOBKEY="primaryKeyName"]
      [BLOBWHERE="primaryKeyValue"]
      [BLOBCOL="column name"]
      [C="asset type"]
      [CID="asset id"]
      [ASSET="asset instance name"]
      [FIELD="asset field name"]
      [BLOBHEADER="MIMEtype"]
      [BLOBNOCACHE="false"]
      [ADDSESSION="true"]
      [DYNAMIC="true"]
      [CSBLOBID="session variable value"]
      [ASSEMBLER="uri assembler shortform"]
      [CONTAINER="servlet|portlet"]
      [FRAGMENT="fragment value"]
      [PARENTID="parent to log this blob as a dependency"]
      [SATELLITE="true|false"]
      [SCHEME="scheme value"]
      [AUTHORITY="authority value"]
      >

      [<RENDER.ARGUMENT NAME="argname" VALUE="argvalue"/>]

</RENDER.GETBLOBURL>

Attributes

outstr (required): Input. Name of the variable that stores the URL generated by this tag.
blobtable (optional): Input. Name of the CS-Direct table that stores assets of this type. For example, blobtable="ImageFile".
blobkey (required, if blobtable set): Input. Name of the column used as the primary key. Typically this is id.
blobwhere (required, if blobtable set): Input. Object ID of the asset.
blobcol (required, if blobtable set): Input. Name of the column that contains the binary data. For example, for the imagefile asset type, blobcol="urlpicture".
field (required, if blobtable not set): Input. The name of an asset field containing binary data to be served.
asset (optional): Input. Name of an asset instance.
c (required, if asset and blobtable not set): Input. An asset type name.
cid (required, if asset and blobtable not set): Input. An asset identifier.
blobheader (optional): Input. Mimetype for returned data, in the form description/extension. For example, the mimetype for a GIF image is image/gif.
blobnocache (optional): Input. Specifies whether to disable blob caching. A value of true prevents the blob from being cached.
addsession (optional): Input. Specifies whether to include session IDs in the URL when a browser is set to reject cookies. true means to encode session IDs in the URL. If this parameter is not specified, it is set to true by default.
dynamic (optional): Input. Specifies whether to create a static or a dynamic URL for the asset when the page is being rendered by the Export to Disk publishing method. true means to create a dynamic URL even if rendermode is set to export. false means to create a static URL if rendermode is set to export. If this parameter is not specified, it is set to false by default.
blobheadernamen (optional): Specifies HTTP header variables to suit your needs, The blobheadername parameter is used in conjunction with the blobheadervalue parameter to produce name/value pairs. This parameter represents the variable name.
blobheadervaluen (optional): Used in conjunction with blobheadername to specify and represent HTTP header variable values.
csblobid (optional): Value of this parameter must correspond to a session variable of the same name when BlobServer security is on. When a request is made to the BlobServer, the img src service parameter sends a new request to the application server after the browser reads the containing page. BlobServer then verifies if the csblobid parameter was set. When BlobServer security is set to true and the csblobid value matches the session variable value, the blob is served. If the values do not match, a security violation is reported and no blob is served
assembler (optional): Short form name for uri assembler class. Specifying an assembler overrides the default assembler used by Content Server to construct URLs. Omitting this value will cause URLs generated by this tag to use the assembler registered with the highest priority in the request property file.
container (optional): Override attribute that specifies whether the URL will be generated for a servlet container or a portlet container. By default, the current container will be used. For practical purposes, leaving this blank or setting it to servlet should be sufficient. Legal values are servlet and portlet.
fragment (optional): Optional attribute to specify a fragment on the URL. Fragments, sometimes known as anchors, allow browsers to advance to a specific location in a single web page. ex. http://www.myhost.com/foo.html#thirdParagraph.
parentid (optional): The id against which this blob should be logged as a dependency. When a blob is cached, an item dependency can be recorded against the cache key to provide a content-based identifier for accessing the cached blob, rather than requiring the cache key to do so. This is useful in cache management. When coupled with an asset identifier, this can allow blobs to be flushed when an asset is updated.
satellite (optional): Override attribute that forces the URL generated to be a URL for either Satellite Server or Content Server. By default, the URL will automatically be set to whatever the containing page is set to. Legal values are true (Satellite Server URL) and false (Content Server URL).
scheme (optional, required if authority is set): Attribute that allows the scheme to be set in the URL. The scheme in the case of most URLs refers to the protocol and is usually set to either http or https. If this is left blank (and authority is left blank) then the URL will be relative to the current scheme and authority.
authority (optional, required if scheme is set): Attribute that allows the user to specify a fully-qualified URL, when used in conjunction with scheme. URLs are of the form scheme://authority/path?query#fragment. For most purposes, authority corresponds to host:port for the given application. Specifying scheme and authority allows for fully-qualified URLs to be created, which is useful for sites with multiple domains and in other cases.

Parameters

render:argument (optional): Input. Name/value modifiers for the blob. Special values to render:argument include:

Description

This tag creates a BlobServer URL.

If rendermode is set to export,the tag creates a static URL; that is, a file name for an HTML file. It creates the URL based on the parameters described in the following section. These are a set of arguments that specify the table the blob is stored in, the name of the column that contains the binary data, the name of the primary key of the table, the value in that column to use to identify the object, and so on.

If rendermode is set to live, the tag creates a dynamic URL according to the current assembler.

Based on this information, RENDER.GETBLOBURL creates a URL for the blob asset and returns it to the element that requested it in a variable specified by the outstr parameter. The requesting element can then use the variable in an HTML tag to create the link.

To create BlobServer URL embedded in an HTML tag, use the RENDER.SATELLITEBLOB tag.

You can use the blobheadername and blobheadervalue parameters to specify http headers in the BlobServer response. For example, you can specify the content-type as follows:

blobheadername1="Content-Type" 
blobheadervalue1="image/gif"

If you want to use http headers to prevent browser caching of BlobServer requests for all browsers, use both HTTP 1.0 and HTTP 1.0 cache control directives. In the following example, the first header (Cache-Control:no-cache) is the HTTP 1.1 directive and the second header (Pragma:no-cache) is the HTTP 1.0 directive.

blobheadername1="Cache-Control" 
blobheadervalue1="no-cache" 

blobheadername2="Pragma" 
blobheadervalue2="no-cache"

NOTE: The table name containing the blob, the primary key of the table, the id of the table row, and the column name that contains the binary data are all optional parameters. The same information can be provided to this tag by specifying an asset type, id and field name, or an asset instance object name and field name. However, there is an advantage to using the latter forms. If the owning asset is changed, Blob Server will invalidate the cached blob, but only if it was served via one of the asset forms of the render:getbloburl tag.

errno

None.

Examples

The following example is in JSP but the XML syntax is analogous. This code creates a BlobServer URL for an ImageFile asset identified through an ID passed in with blobwhere='<%=ics.GetVar("asset:id")%>' and stores it in a variable named "theURL":

<render:getbloburl 
        blobtable="ImageFile" 
        blobcol="urlpicture" 
        blobheader='<%=ics.GetVar("asset:mimetype")%>' 
        blobkey="id" 
        blobwhere='<%=ics.GetVar("asset:id")%>' 
        outstr="theURL"/>

This code does the same, except the cached blob will be invalidated when the corresponding ImageFile asset is modified:

<render:getbloburl 
        c="ImageFile" 
        field="urlpicture" 
        blobheader='<%=ics.GetVar("asset:mimetype")%>' 
        cid='<%=ics.GetVar("asset:id")%>' 
        outstr="theURL"/>

This code does the same, except uses an already-loaded imagefile asset instead:

<asset:load 
       name="myasset" 
       type="ImageFile" 
       objectid='<%=ics.GetVar("asset:id")%>'/>
<render:getbloburl 
        asset="myasset" 
        field="urlpicture" 
        blobheader='<%=ics.GetVar("asset:mimetype")%>' 
        outstr="theURL"/>