PRTG Manual: HTTP XML/REST Value Sensor

Channel Name

Enter a name for the channel which will display the value at the given URL. The name can be changed later in the Sensor Channels Settings.

Sensor Name

Enter a meaningful name to identify the sensor. The name will be shown by default in the device tree and in all alarms.

Tags

Enter one or more tags, separated by space or comma. You can use tags to group sensors and use tag-filtered views later on. Tags are not case sensitive. We recommend using the default value. You can add additional tags to it, if you like. Other tags are automatically inherited from objects further up in the device tree. Those are not visible here.

Priority

Select a priority for the sensor. This setting determines where the sensor will be placed in sensor lists. Top priority will be at the top of a list. You can choose from one star (low priority) to five stars (top priority).

URL

Enter the absolute URL that returns the XML file (this sensor does not use the IP Address/DNS value of the parent device).

XML Node (and optional property)

Enter the name of the node this sensor will check, or enter a node name and a property name to check a property value. To obtain a value from nested tags, please enter the tag names separated by a slash symbol, e.g. use myTag/myTagInside as XML node value. Note: XPath  syntax is allowed here. This enables you, for example, to read values of arrays from XML files. For example, use array[@name='myName'] to read all 'array' elements which have a 'name' attribute equal to 'myName'. For further documentation about XPath please see More section below. Note: You can also check values in JavaScript Object Notation (JSON) notation. Please see Checking JSON section below.

HTTP Username

If the URL requires authentication, enter the username. Please enter a string or leave the field empty.

HTTP Password

If the URL requires authentication, enter the password. Please enter a string or leave the field empty.

Sensor Value

Choose between:

• Use the value of the selected XML node: Return the value found at the specified XML node. If this is non-numeric, this will return 0.

• Use the number of occurrences of the selected XML node or its children/siblings: Return the number of occurrences found. Define further below.

Count XML Nodes

This setting is only visible if the return number option is enabled above. Define which count will be returned. Choose between:

• Occurrences of the selected XML node: Return how often the defined XML node occurs at the defined URL.

• Child nodes of the selected XML node: Return the number of child nodes that exist below the node at the defined URL.

• Sibling nodes of the selected XML node: Return the number of sibling nodes that exist next to the node at the defined URL.

Namespaces

Define whether namespaces in the XML document will be used or not. Choose between:

• Use Namespaces: Process the value entered in the "XML Node (and optional property)" field including possibly existing namespace information.

• Remove Namespaces: Ignore namespace information in the XML document and process the value entered in the "XML Node (and optional property)" field as node names only.

For more information see About Namespaces section below.

Content Type in Header

Choose if PRTG will Include content-type="text/xml" in the header of the request sent to the URL defined above. Choose between:

• Enable (recommended): This works for most web servers and is the recommended setting.
• Disable: Only very few web servers cannot handle this content-type and need this setting. Try this if you get an error message with the enabled option.
• Custom: You can use a custom content type.

Custom Content Type

Only visible when "Custom" is enabled above. Enter a custom content type like text/xml or text/html.

Characters to Remove

Only visible when using value of XML node is enabled above. Optionally enter a string which will be removed from the returned XML value. Use this to remove any unwanted characters from the result, e.g. a thousands separator from numeric values. Please enter a string or leave the field empty.

Custom Message

Optionally enter a custom sensor message. Use %1 as a placeholder to automatically fill in the returned XML value. Please enter a string or leave the field empty.

Force SSL V3

Define if you only want to allow SSL V3 connections to the URL defined above. Choose between:

• No

• Yes

If Value Changes

Define what shall be done in case the value of this sensor changes. You can choose between:

• Ignore changes (default): No action will be taken on change.
• Trigger 'change' notification: The sensor will send an internal message indicating that its value has changed. In combination with a Change Trigger, you can use this mechanism to trigger a notification whenever the sensor value changes.

Results

Define what will be done with the results given back. Choose between:

• Discard result: Do not store the requested web page.
• Write result to disk (Filename: "Result of Sensor [ID].txt"): Store the last result received from to the "Logs (Sensors)" directory (on the Master node, if in a cluster). This is for debugging purposes. The file will be overridden with each scanning interval. For information on how to find the folder used for storage, please see More section below.

Unit String

Enter a string that will be added to the values as a unit description. This is for display purposes only.

Primary Channel

Select a channel from the list to define it as the primary channel. In the device tree, the last value of the primary channel will always be displayed underneath the sensor's name. The available options depend on what channels are available for this sensor. Note: You can set another primary channel later by clicking on the pin symbol of a channel in the sensor's overview tab.

Chart Type

Define how different channels will be shown for this sensor.

• Show channels independently (default): Show an own graph for each channel.

• Stack channels on top of each other: Stack channels on top of each other to create a multi-channel graph. This will generate an easy-to-read graph which visualizes the different components of your total traffic. Note: This option cannot be used in combination with manual Vertical Axis Scaling (available in the Sensor Channels Settings settings).

Stack Unit

This setting is only available if stacked graphs are selected above. Choose a unit from the list. All channels with this unit will be stacked on top of each other. By default, you cannot exclude single channels from stacking, if they use the selected unit. However, there is an advanced procedure to do so.

Scanning Interval

Scanning Interval

The scanning interval determines the time the sensor waits between two scans. Select a scanning interval (seconds, minutes, or hours) from the list. You can change the available intervals in the system administration.

Note: Inheritance for schedules, dependencies, and maintenance windows cannot be interrupted; the according settings from the parent objects will always be active. However, you can define additional settings here. They will be active in parallel to the parent objects' settings.

Schedule

Select a schedule from the list. Schedules can be used to monitor for a certain time span (days, hours) throughout the week. With the period list option it is also possible to pause monitoring for a specific time span. You can create new schedules and edit existing ones in the account settings. Note: Schedules are generally inherited. New schedules will be added to existing ones, so all schedules are active.

Maintenance Window

Specify if you want to set-up a one-time maintenance window. During a maintenance window this object and all child objects will not be monitored. They will enter a paused state then. Choose between:

• Not set (monitor continuously): No maintenance window will be set.
• Set up a one-time maintenance window: Pause monitoring within a maintenance window.

Maintenance Begins At

This field is only visible if maintenance window is enabled above. Use the date time picker to enter the start date and time of the maintenance window.

Maintenance End At

This field is only visible if maintenance window is enabled above. Use the date time picker to enter the end date and time of the maintenance window.

Dependency Type

Define a dependency type. Dependencies can be used to pause monitoring for an object depending on the status of another. You can choose between:

• Use parent: Pause the current sensor if the device it is created on is in a Down status, or if it is paused by another dependency.
• Select object: Pause the current sensor if the device it is created on is in an Down status, or if it is paused by another dependency. Additionally, pause the current sensor if a specific other object in the device tree is in a Down status, or if it is paused by another dependency. Select below.
• Master object for parent: Make this sensor the master object for its parent device. The sensor will influence the behavior of the device it is created on: If the sensor is in a Down status, the device will be paused. For example, it is a good idea to make a Ping sensor the master object for its parent device to pause monitoring for all other sensors on the device in case the device cannot even be pinged. Additionally, the sensor will be paused if the parent group of its parent device is in a Down status, or if it is paused by another dependency.

Note: Testing your dependencies is easy! Simply choose Simulate Error Status from the context menu of an object that other objects depend on. A few seconds later all dependent objects should be paused.

Dependency

This field is only visible if the select object option is enabled above. Click on the reading-glass symbol and use the object selector to choose an object on which the current sensor will be dependent on.

Delay (Seconds)

Define a time span. After the master object for this dependency comes back to an Up status, monitoring of the depending objects will be additionally delayed by the defined time span. This can help avoid false alarms, for example, after a server restart, by giving systems more time for all services to start up. Please enter an integer value in seconds. Note: This setting is not available if you choose this sensor to be the Master object for parent. In this case, please define delays in the parent Device Settings or the superior Group Settings.

Access Rights

User Group Access

Define which user group(s) will have access to the object you're editing. A table with user groups and right is shown; it contains all user groups from your setup. For each user group you can choose from the following access rights:

• Inherited: Use the settings of the parent object.
• None: Users in this group cannot see or edit the object. The object does not show up in lists and in the device tree. Exception: If a child object is visible to the user, the object is visible in the device tree, though not accessible.
• Read: Users in this group can see the object and review its monitoring results.
• Write: Users in this group can see the object, review its monitoring results, and edit the object's settings. They cannot edit access rights settings.
• Full: Users in this group can see the object, review its monitoring results, edit the object's settings, and edit access rights settings.

You can create new user groups in the System Administration—User Groups settings. To automatically set all objects further down in the hierarchy to inherit this object's access rights, set a check mark for the Revert children's access rights to inherited option.

For more details about access rights, please see section User Access Rights.

Channel Unit Configuration

Channel Unit Types

For each type of sensor channel, define the unit in which data is displayed. If defined on probe, group, or device level, these settings can be inherited to all sensors underneath. You can set units for the following channel types (if available):

• Bandwidth
• Memory
• Disk
• File
• Custom

Note: Custom channel types can be set on sensor level only.

Example

A JSON notated section may look like the following:

{
  "test": "Hello World",
  "object": {
    "value": "content",
    "AnotherValue": "AnotherContent"
  },
  "arraytest": [
    "one",
    "two"
  ]
}

Depending on your entries in the XML Node field, the sensor will process the respective values:

Example

A namespace notated section may look like the following:

<myNamespace:myNode>
  some information
</myNamespace:myNode>