Forms: HTTP Collector

An HTTP Collector reads data from a HTTP Datasource. The collector defines how the data needed from the datasource will be extracted to be used in CenterView.

Form: HTTP Collector Details

The HTTP Collector form contains a number of tabs:

Field	Description
Details	The main details required for HTTP Collector configuration.
Send Message	Define details of the HTTP request sent to the HTTP Datasource to get the data required.
HTTP Headers	For an HTTP request, define name value pairs to include as part of the HTTP header. (e.g. content-type)
Response	Define the data response type/format that will be returned: HTML: response type allows an XPath Expression to be specified in order to retrieve just specified sections of the data into XML structures. XML: response type allows an XPath Expression to be specified in order to retrieve just specified sections of the data into XML structures. XML response types also support XML namespaces. The Xml Namspaces tab will be available when this response type is chosen. String: response type will return the full data as a string value. Please see Response Examples for how the returned data can be used and evaluated in the corresponding stream attribute expressions.
XML Namespaces	The namespaces defined in an XML response. The names given to these namespaces must match those used in any Xpath expressions used to extract data from an XML response. See examples below.
Description	A free text field for you to enter a description of the HTTP Collector.

The following fields are configured on the Details tab:

Field	Description
Name	Name of the HTTP Collector.
HTTP Data Source	The HTTP datasource that this collector will collect from.
Enabled	Tick when the configuration is complete and the collector is ready to be used.
Allow Non-Scheduled Collection	If this is turned on, then the collector will run as part of any ad-hoc Analysis Engine run which requires this data. If not, it will only run as part of a scheduled Task Plan under the Analysis Engine.
Icon	The Icon to display in controls when this collector is used.
Timeout (secs)	The number of seconds to wait for a response from the corresponding HTTP datasource before a timeout is recorded.
Datasource Instance Expression	The datasource to which this collector is connected may list multiple instances from which the data may be accessed. Each HTTP Datasource Instance is identified by a unique string. This expression should evaluate to a string which allows the collector to determine the specific instance to use. If the expression is blank then the collector will assume that there is only one instance and will use that one by default. If there is more than one instance and no expression is provided here then an error will be thrown during analysis since the collector will be unable to determine which source to use.

The following fields are configured on the Send Message tab:

Field

Description

URL Expression

The URL to be used, without the leading http:// prefix. The URL may contain embedded expressions within { }. If this field is blank, the url field on the httpDatasourceInstance is used directly.

For Example, this expression adds to the base url provided by the HTTP Datasource Instance :

{_url}/sub1/sub2?param1=3

Statement Expression

An expression to generate the data that will be sent by the exporter to the datasource. For Example

<?xml version ="1.0"?> <!DOCTYPE CORPORATE DASHBOARD "corpDash.dtd"> <results user="%USERNAME%" password="%PASSWORD%"> <monthlyTotals region={'"' + Region + '"'} division={'"' + Division + '"'}> <totalBilled>{'"' + TotalBilled + '"'}<\totalBilled> <totalCollected>{'"' + TotalCollected + '"'}<\totalCollected> <monthlyTotals> <\results>

The following fields are configured on the Response tab:

Field	Description
Response Type	The type of the expected response : XML/HTTP/String
XPath	The XPath expression used to resolve or filter the data that comes back in XML or HTML format. Note that Xpath namespaces syntax can only be used for XML response types.

The following fields are configured on the Description tab:

Field	Description
Description	A freeform description of the HTTP collector.

Reponse Examples

Given the following XML and HTML data that is being pointed to by either HTTP datasources or XML/HTML File collectors respectively.

XML Data <?xml version ="1.0"?> <root xmlns:h="http://www.w3.org/TR/html4/"> <main page="CV Main Page" > <h:title h:name="CV Title">CV Title Text <h:datarow> <h:data h:initials="AD">Ali Dawson</h:data> <h:data h:initials="GP">Gary Parden</h:data> </h:datarow> </h:title> <title name="Non namespace Title">Non namespace Title Text</title> </main> </root>
HTML Data <html> <body nodename="Html Body"> <table> <tbody> <tr> <td initials="AD">Ali Dawson</td> <td initials="GP">Gary Parden</td> </tr> </tbody> </table> </body> </html>

The following table shows the different types of responses that can be returned from an HTTP Collector and how these can be used in the corresponding stream attribute expressions. A HTTP Collector response type of XML/HTML will mimic the responses from XML/HTML Collectors respectively.

Response Type

XPath Expression

Explanation

String

n/a

A String response should be referenced in the stream attribute expressions as in.value Note that in.value will contain the complete string data referenced above.

XML

/root/main/h:title

Note that the namspace prefix used here 'h' must be configured in the HTTP XML Namspaces form

This XPath expression will bring back all elements matching the xpath expression including the parent/grandparents and all child elements/subelements. i.e

<root xmlns:h="http://www.w3.org/TR/html4/"> <main page="CV Main Page" > <h:title h:name="CV Title">CV Title Text <h:datarow> <h:data h:initials="AD">Ali Dawson</h:data> <h:data h:initials="GP">Gary Parden</h:data> </h:datarow> </h:title> </main> </root>

The following examples show how to reference the returned xpaths html/xml data structure in stream attribute expressions:-

Xpath element text value: in.value -> returns 'CV Title Text'
Xpath element attibutes: in.h$name -> returns 'CV Title'
Xpath parent attributes: in.^.page -> returns 'CV Main Page'
Xpath child attributes: listToString(in.h$datarow.h$data.h$initials) -> returns 'AD,GP'
Xpath child attribute text values: listToString(in.h$datarow.h$data.value) -> returns 'Ali Dawson,Gary Parden'

Note the use of a $ instead of our usual : namespace notation.

Note the use of a ^ to traverse to the immediate parent element.

Note the use of the listToString function to handle multiple matching child elements/attributes.

HTML

/html/body/table

Note that namspaces are not supported in the Xpath expression for HTML response types

This XPath expression will bring back all elements matching the xpath expression including the parent/grandparents and all child elements/subelements. i.e

<html> <body nodename="Html Body"> <table> <tbody> <tr> <td initials="AD">Ali Dawson</td> <td initials="GP">Gary Parden</td> </tr> </tbody> </table> </body> </html>

The following examples show how to reference the returned xpaths html/xml data structure in stream attribute expressions:-

Xpath parent attributes: in.^.nodename -> returns 'Html Body'
Xpath child attributes: listToString(in.tbody.tr.td.initials) -> returns 'AD,GP'
Xpath child attribute text values: listToString(in.tbody.tr.td.value) -> returns 'Ali Dawson,Gary Parden'

Note the use of a ^ to traverse to the immediate parent element.

Note the use of the listToString function to handle multiple matching child elements/attributes.

Note the use of the optional html <tbody> tags. If these are not in your html data, then centerview will insert them to conform with the HTML standards. Therefore when using absolute XPath expressions, note that the tbody tags need to be included even if they are not present in the incoming HTML data.
i.e /html/title/table/tr should be replaced with /html/title/table/tbody/tr. Alternativley you can use //tr
The same applies when referencing parent/child nodes within the stream attribute expressions.

Default XML namespaces

The following example illustrates how a default namespace defined in an XML response is handled.

<?xml version="1.0" encoding="UTF-8"?> <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns="urn:xmlns:company-com:message" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:cv="urn:centerview.message.com"> <soapenv:Body> <queryResponse> <result xsi:type="QueryResult"> <done>true</done> <queryLocator xsi:nil="true"/> <record xsi:type="cv:sObject"> <cv:type>Account</cv:type> <cv:Name>Company1</cv:Name> <cv:CreatedDate>2013-10-31T11:26:21.000Z</cv:CreatedDate> </record> <record xsi:type="cv:sObject"> <cv:type>Account</cv:type> <cv:Name>Company2</cv:Name> <cv:CreatedDate>2013-10-31T11:26:21.000Z</cv:CreatedDate> </record> <size>2</size> </result> </queryResponse> </soapenv:Body> </soapenv:Envelope>

Since this document uses a default namespace ("urn:xmlns:company-com:message"), to refer to any element in an XPath expression that does not explicitly use a namespace you must use the default namespace. So to extract all record elements, you must first define a namespace in the collector for the default namespace. Suppose that you do and give this the name def. Then the XPath (defined in the XPath field on the Response tab) to extract all record elements will be //def:record

In a Stream that reads from this collector, any other namespaces defined in the document are used as normal. For example, to write the value from the element Name within each record element to a Stream attribute, you would use the attribute expression in.sf$Name

Form Icons

The form provides the standard form icons

HELP59

httpCollector

Forms: HTTP Collector

Form: HTTP Collector Details

Reponse Examples

Default XML namespaces

Form Icons

See Also