PRTG Manual: HTTP XML/REST Value Sensor
The HTTP XML/REST Value sensor retrieves an XML file from a given URL and parses it.
- It can show the value of one defined XML node.
Dutch: HTTP XML/REST Waarde, French: Valeur HTTP XML/REST, German: HTTP XML-/REST-Wert, Japanese: HTTP XML/REST値, Portuguese: Valor HTTP XML/REST, Russian: Значение HTTP XML/REST, Simplified Chinese: HTTP XML/REST 值, Spanish: Valor HTTP XML/REST
- Requires .NET 4.7.2 or later on the probe system. If the sensor shows the error PE087, please additionally install .NET 3.5 on the probe system.
- This sensor can monitor only one single node in an XML file and shows the value in one channel. If you need to monitor more than one node of an XML document, please add the sensor for each target node anew.
- Supports Smart URL Replacement.
- We recommend Windows 2012 R2 on the probe system for best performance of this sensor.
- Knowledge Base: HTTP XML/REST Value Sensor: FAQ
- Knowledge Base: Which HTTP status code leads to which HTTP sensor status?
- This sensor type does not support Secure Remote Password (SRP) ciphers.
- This sensor type can have a high impact on the performance of your monitoring system. Please use it with care! We recommend that you use no more than 50 sensors of this sensor type on each probe.
This sensor type requires the Microsoft .NET Framework version 4.7.2 or later to be installed on the computer running the PRTG probe, either on the local system (on every node, if on a cluster probe), or on the system running the remote probe. If the framework is missing, you cannot create this sensor.
For more information, see the Knowledge Base: Which .NET version does PRTG require?
PRTG does not officially support more than 50 sensor channels. Depending on the data used with this sensor type, you might exceed the maximum number of supported sensor channels. In this case, PRTG will try to display all sensor channels. However, please be aware that you will experience limited usability and performance.
The Add Sensor dialog appears when you manually add a new sensor to a device. It only shows the setting fields that are required for creating the sensor. Therefore, you will not see all setting fields in this dialog. You can change (nearly) all settings in the sensor's Settings tab later.
The following settings for this sensor differ in the Add Sensor dialog in comparison to the sensor's Settings tab.
Sensor Settings |
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Channel Name |
Enter a name for the channel that will display the value at the given URL. |
On the details page of a sensor, click the Settings tab to change its settings.
Usually, a sensor connects to the IP Address or DNS Name of the parent device where you created this sensor. See the Device Settings for details. For some sensor types, you can define the monitoring target explicitly in the sensor settings. See below for details on available settings.
Basic Sensor Settings |
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Sensor Name |
Enter a meaningful name to identify the sensor. By default, PRTG shows this name in the device tree, as well as in alarms, logs, notifications, reports, maps, libraries, and tickets. |
Parent Tags |
Shows Tags that this sensor inherits from its parent device, group, and probe. This setting is shown for your information only and cannot be changed here. |
Tags |
Enter one or more Tags, separated by spaces or commas. You can use tags to group sensors and use tag–filtered views later on. Tags are not case sensitive. We recommend that you use the default value. You can add additional tags to the sensor if you like. Other tags are automatically inherited from objects further up in the device tree. These are visible above as Parent Tags.
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Priority |
Select a priority for the sensor. This setting determines where the sensor is placed in sensor lists. Top priority is at the top of a list. Choose from one star (low priority) to five stars (top priority). |
Sensor Settings |
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URL |
Enter the URL that returns the XML file. It has to be URL encoded! If you enter an absolute URL, the sensor uses this address independently of the IP Address/DNS Name setting of the device on which you create this sensor. PRTG uses a smart URL replacement that allows you to use the parent device's IP address/DNS name setting as part of the URL.
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XML Node (and optional property) |
Enter the name of the node that this sensor checks, or enter a node name and a property name to check a property value. To obtain a value from nested tags, enter the tag names separated by a slash symbol, for example, use myTag/myTagInside as XML node value.
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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 |
Define what value this sensor shows. Choose between:
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Count XML Nodes |
This setting is only visible if you enable the return number option above. Define which count the sensor shows. Choose between:
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Namespaces |
Define whether namespaces in the XML document are used or not. Choose between:
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Content Type in Header |
Define what to include in the header of the request sent to the URL defined above. Choose between:
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Custom Content Type |
This field is only visible when you enable the Custom option above. Enter a custom content type like text/xml or text/html. |
HTTP Headers |
Optionally enter a list of custom HTTP headers with their respective values that you want to transmit to the URL you define above. The syntax of a list with header-value pairs is header1:value1|header2:value2|...|headerx:valuex
Example: From:[email protected]|AcceptLanguage:en-us
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Characters to Remove |
This field is only visible if you enable the Use the value of the selected XML node option above. Optionally enter a string that the sensor removes from the returned XML value. Use this to remove any unwanted characters from the result, for example, a thousands separator from numeric values. Please enter a string or leave the field empty. |
Decimal Delimiter |
This setting is only visible if you enable the Use the value of the selected XML node option above. If the sensor value of the selected XML node is of the type float, you can define any character here, which is then handled as the decimal delimiter. Enter one character 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. |
If Channel Value Changes |
Define what this sensor will do when the sensor value changes. You can choose between:
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Unit String |
Enter the unit for the values that this sensor returns. Please enter a string. This unit string is used for display purposes and will be shown in graphs, data tables, and gauges. If you want to change the Unit after having created the sensor, you can change it in the sensor's channel settings. |
Debug Options |
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Sensor Result |
Define what PRTG will do with the sensor results. Choose between:
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Sensor Display |
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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 below the sensor's name. The available options depend on what channels are available for this sensor.
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Graph Type |
Define how different channels will be shown for this sensor.
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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. |
By default, all following settings are inherited from objects higher in the hierarchy and should be changed there, if necessary. Often, best practice is to change them centrally in the Root group's settings, see section Inheritance of Settings for more information. To change a setting only for this object, disable inheritance by clicking the button next to inherit from under the corresponding setting name. You will then see the options described below.
Scanning Interval |
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Click |
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Scanning Interval |
Select a scanning interval (seconds, minutes, or hours) from the list. The scanning interval determines the time the sensor waits between two scans. You can change the available intervals in the system administration on PRTG on premises installations. |
If a Sensor Query Fails |
Define the number of scanning intervals that a sensor has time to reach and check a device again in case a sensor query fails. The sensor can try to re-reach and check a device several times, depending on the option you select here, before it will be set to a Down status. This helps you avoid false alarms if the monitored device has only temporary issues. For previous scanning intervals with failed requests, the sensor will show a Warning status. Choose between:
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Schedules, Dependencies, and Maintenance Window |
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Schedule |
Select a schedule from the list. Schedules can be used to monitor for a certain time span (days, hours) every 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.
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Maintenance Window |
Specify if you want to set up a one-time maintenance window. During a "maintenance window" period, this object and all child objects will not be monitored. They will be in a Paused status instead. Choose between:
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Maintenance Begins |
This field is only visible if you enabled the maintenance window above. Use the date time picker to enter the start date and time of the maintenance window. |
Maintenance Ends |
This field is only visible if you enabled the maintenance window 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:
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Dependency |
This field is only visible if the Select object option is enabled above. Click on the reading-glasses and use the object selector to choose an object on which the current sensor will depend. |
Dependency Delay (Sec.) |
Define a time span in seconds for a dependency delay. After the master object for this dependency goes back to Up status, PRTG will start monitoring the depending objects after this extra delayed. This can help to 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.
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Access Rights |
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Click |
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User Group Access |
Define which user group(s) will have access to the object you're editing. A table with user groups and types of access rights is shown. It contains all user groups from your setup. For each user group, you can choose from the following access rights:
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.
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Channel Unit Configuration |
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Click |
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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):
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With the XML Node (and optional property) field, you can also check values that are returned in JavaScript Object Notation (JSON) notation under the defined URL.
A JSON notated section may look like the following: {
Depending on your entries in the XML Node field, the sensor will process the respective values:
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The sensor converts whitespaces in JSON keys into underscores (_). So, for example, if you look for the node some node in the JSON, you need to enter some_node into the node field. If you count the number of nodes (for example, some_node), both some node and some_node would be counted if they appear in the JSON.
If a key exists more than once in the JSON, the value of the first appearance is returned (no difference between whitespace and underscore).
In an XML document, tags may use namespaces.
A namespace notated section may look like the following: <myNamespace:myNode>
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If you set this sensor to Use namespaces (this is the default setting), it will expect the full node name, including the namespace information, in the XML Node (and optional property) field. In the example above, this would be myNamespace:myNode.
If your node names are unique even without the namespace information, you can simplify the settings by setting this sensor to Remove namespaces. The sensor will then expect the node name only in the XML Node (and optional property) field. In the example above, this would be myNode.
Instead of entering a complete address in the URL field of an HTTP sensor, you can merely enter the protocol followed by a colon and three slashes (that means you can enter either http:/// or https:/// or even a simple slash / as equivalent for http:///). PRTG will fill in the parent device's IP address or DNS name in front of the third slash automatically.
Whether this results in a valid URL or not depends on the IP address or DNS name of the device where this HTTP sensor is created on. In combination with cloning devices, the smart URL replacement makes it easy to create many like devices.
For example, if you create a device with DNS name www.example.com and you add an HTTP sensor to it, you can provide values in the following ways:
- Providing the value https:/// in the URL field, PRTG will automatically create the URL https://www.example.com/
- Using the value /help in the URL field, PRTG will automatically create and monitor the URL http://www.example.com/help
- It is also possible to provide a port number in the URL field, which will be taken over by the device's DNS name and internally added, for example, http://:8080/
Smart URL replacement does not work for sensors running on the Probe Device.
Knowledge Base: Which HTTP status code leads to which HTTP sensor status?
Knowledge Base: Is there a tool available that can help me building queries for the XML/Rest Sensor?
Knowledge Base: How do I extract values from XML nodes (with nested tags) using PRTG's XML/Rest Value Sensor?
Knowledge Base: How can I use XPath with PRTG's XML/Rest Value Sensor?
Knowledge Base: Why does my HTTP XML/REST Value Sensor return a 404 error?
Knowledge Base: For which sensor types do you recommend Windows Server 2012 R2 and why?
Knowledge Base: Which .NET version does PRTG require?
To change display settings, spike filter, and limits, switch to the sensor's Overview tab and click the gear icon of a specific channel. For detailed information, see the Sensor Channel Settings section.
Click the Notification Triggers tab to change notification triggers. For detailed information, see the Sensor Notification Triggers Settings section.
For more general information about settings, see the Object Settings section.
For information about sensor settings, see the following sections: