Home >	Contents >	Index >
Template Tag TOC  |   Alpha TOC  |   Tag Family TOC  |   Purpose TOC  |   Annotated TOC  |   Index

RENDER.SATELLITEBLOB

Creates a URL in a complete HTML tag that retrieves a blob from a table or from the CS-Satellite cache.

Syntax

<RENDER.SATELLITEBLOB 
      SERVICE="HTMLtagName"
      [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"]
      [ARGS_format1="5"]
      [CACHECONTROL="expirationDateAndTime"
      [BLOBLHEADERNAMEN="blob header name"]
      [BLOBHEADERVALUEN="blob header value"] 
      [CSBLOBID="session variable value" />

Parameters

SERVICE (required)

Input. The start of the HTML tag to hold the reference to the blob. For example, if the blob is an image, use SERVICE="IMG SRC".

BLOBTABLE (optional)

Input. Name of a ContentServer database table that stores binary data. For example, BLOBTABLE="ImageFile".

BLOBKEY (required, if BLOBTABLE set)

Input. Name of the database column used as the primary key. Typically, this is id.

BLOBWHERE (required, if BLOBTABLE set)

Input. Primary key value describing the row containing the binary data to be served.

BLOBCOL (required, if BLOBTABLE set)

Input. Name of the database table column that contains the binary data. For example, for the Imagefile database table, 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 (required)

The mimetype for returned data, in the form description/extension. For example, the mimetype for a GIF image is image/gif.

ARGS_ (optional)

Input. Name/value modifiers for the HTML tag, with the string ARGS_as the prefix. For example, ARGS_vspace="5", ARGS_hspace="5", and so on.

CACHECONTROL (optional)

Input. Determines for how long to cache the blob. See satellite.blob for details about this parameter.

BLOBHEADERNAMEN (optional)

This parameter set specific 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.

BLOHEADERVALUEN (optional)

This parameter is used in conjunction with BLOBHEADERNAME to specify and represent HTTP header variable values.

CSBLOBID (optional)

The 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.

Description

This tag is the CS-Direct equivalent of the CS-Satellite SATELLITE.BLOB tag, with the following exception:

• rendermode is passed in automatically.

You can use BLOBHEADERNAME and BLOBHEADERVALUE 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"

To determine how long to cache a page or pagelet, these criteria are evaluated in this order:

1. A value passed in using the CACHECONTROL parameter.

2. If there is no value in CACHECONTROL, the value in the satellite.page.cachecontrol.default property, found in the futuretense.ini property file, is used.

3. If there is no value in satellite.page.cachecontrol.default, the value of the expiration property, located in the satellite.ini property file, is used.

We recommend that you set values for the satellite.page.cachecontrol.default properties that make sense for the majority of your pages and pagelets.  If you want to override the default expiration time, use the CACHECONTROL parameter.  Use the expiration property to determine the timeout for pages that are not generated from this tag; for example, pages that are generated directly from a URL.

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.SATELLITEBLOB tag.

errno

None.

Examples

This code creates an HTML <IMG SRC> tag. The SRC is the blob in the ImageFile table identified through the ID passed in with BLOBWHERE="Variables.asset:id" and both its horizontal and vertical spacing are at five pixels:

<RENDER.SATELLITEBLOB BLOBTABLE="ImageFile" BLOBKEY="id" BLOBCOL="urlpicture" BLOBWHERE="Variables.asset:id" BLOBHEADER= "Variables.asset:mimetype" SERVICE="IMG SRC" ARGS_alt= "Variables.asset:alttext" ARGS_hspace="5" ARGS_vspace="5" />

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

<RENDER.SATELLITEBLOB C="ImageFile" FIELD="urlpicture" CID="Variables.asset:id" BLOBHEADER= "Variables.asset:mimetype" SERVICE="IMG SRC" ARGS_alt= "Variables.asset:alttext" ARGS_hspace="5" ARGS_vspace="5" />

This code does the same thing, but uses an already-loaded asset instance:

<ASSET.LOAD TYPE="ImageFile" OBJECTID="Variables.asset:id" NAME="myasset"/>
<RENDER.SATELLITEBLOB ASSET="myasset" FIELD="urlpicture" BLOBHEADER= "Variables.asset:mimetype" SERVICE="IMG SRC" ARGS_alt= "Variables.asset:alttext" ARGS_hspace="5" ARGS_vspace="5" />

See Also

RENDER.SATELLITEPAGE
satellite.blob

		Home >	Contents >	Index >
	FatWire XML Tag Reference Copyright 2005 by FatWire Software All rights reserved.