After the data has been cleaned up, standardized, and transformed into an analyzable format, companies need a platform to help extract insights from the data. Tableau is a popular Data Visualization tool used worldwide for Data Analysis and Business Intelligence. Its flexibility and user-friendly interface enable business analysts to effectively create and design dashboards, charts, and graphs simplifying the decision-making process.
The web is a great source of data published in XML, HTML, and JSON formats. You can use the Tableau Web Data Connector to set a connection with virtually any site and extract data. You can create your own WDC or use connectors that were created by others.
In this article, you will learn how to effectively use the Tableau Web Data Connector.
What is Tableau?
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Tableau is a widely used Data Visualization tool for Data Analytics and Business Intelligence. Launched in 2003, Tableau allows you to build visually stunning and informative charts, graphs, maps, dashboards, and stories for visualizing and analyzing data, to help in making business decisions.
This powerful tool can effectively handle structured, semi-structured, and unstructured data. With its easily accessible functions, you can create highly simplified graphs or charts for any set of complex data.
Key Features of Tableau
Tableau offers some of the most eye-catching features in the Business Intelligence industry:
- User-Friendly: This platform doesn’t require you to have any prior programming knowledge. You can get started in minutes and begin creating visualizations using Tableau.
- Flexibility: Using Tableau, you can extract data from databases like pdf, excel, text documents, R, Hadoop, Python, or SAS to cloud databases like Flipkart, Google sheet, Netflix, Amazon.
- Robust: You can accurately create reports by joining and blending different datasets. Its powerful data discovery and exploration allow you to answer vital questions in seconds.
- Tableau Server: It also provides a centralized location to effectively manage & maintain all published data sources within an organization. With the published data you can enjoy features such as collaboration, models of security, automation, distribution, etc.
What is a Tableau Web Data Connector?
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A Tableau Web Data Connector (WDC) is a web page that allows you to set a data connection that can be accessed over HTTP to a data source that Tableau does not yet have a connector for. WDC allows users to connect to almost any data accessible over the Internet and build extracts for their workbooks.
A web data connector is an HTML file that contains JavaScript code. You can create your own web data connector or use the one built by others. The web data connector must be hosted on a web server running locally on your computer, a web server in your domain, or a third-party web server.
Key Benefits and Use Cases of Tableau Web Data Connector
Tableau Web Data Connector is a powerful tool that offers the following benefits:
- Tableau WDC allows you to develop a custom connection with data present on the web, efficiently extract it, and make it available on Tableau.
- You can build your own WDC to extract data JSON, XML, or HTML from internal web services, REST APIs, and other sources that are available over HTTP or HTTPS.
- Allows user interaction through forms for selection and filtering.
Key Considerations while Vetting Tableau Web Data Connectors
The Tableau Web Data Connector (WDC) is coded in JavaScript, which usually connects to data from another site. For this reason, users should test and validate the Tableau Web Data Connector before using it as a data source for workbooks and before using it with Tableau Server. To ensure the proper working of the Tableau Web Data Connector, you can consider going through the following checklist:
1. Monitoring the Traffic Created by Tableau WDC
Several Tools for testing a Web Data Connector are available in the market such as Fiddler, Charles HTTP Proxy, Wireshark, etc. They check the requests and responses made by the connector.
Check that you clearly understand which sites the connector requests and what content the connector requests. Make sure to monitor and check the responses and their content so that the connector doesn’t read data or code that is unrelated to the connector’s purpose.
2. Testing the Web Data Connector in an Isolated Environment
It is always a good practice to test your Tableau Web Connector in an isolated environment that is away from your production environment & the user’s computer. For instance, you can include your web data connector to the safe list of test computers or virtual machines running a non-production version of Tableau Server.
3. Testing the Resource Usage and Performance of the Web Connector
You can use tools to keep a tab on your CPU and memory usage when testing the web data connector. Note that the Web Data Connector runs on Tableau Server, an environment where already there are several processes running in the background. When retrieving data, you need to ensure that the connector does not excessively impact server performance.
Also, check if the connector is writing to disk. If so, you should try to examine the amount of disk space WDC is using as well as the output to make sure that you completely understand what the Tableau Web Data Connector is writing and why.
4. Examining the Source
Since the Web Data Connector code is in Javascript, you easily examine & edit all the files used by the connector. Many connectors refer to external JavaScript libraries such as jQuery and third-party API libraries. Make sure the URL of the external library points to a trusted location in the library.
For instance, if your connector references a jQuery library, ensure that the library is on a website that is considered safe by default. If is it possible to modify the source code, then It is also recommended to use the HTTPS protocol (https: //) to point to the external library (if the source site supports HTTPS) and check the authenticity of the site.
At last, make sure you understand what your code is doing. In particular, make sure you understand how the code sends the request to an external website and the information that the request sends.
How to Connect a Data Source through Tableau Web Data Connector
To connect a data source to Tableau, you can follow the simple steps given below:
- Step 1: Open Tableau and navigate to Connect > Web Data Connector. To view the full set of available data connections, go to To a Server > More.
- Step 2: Type in your Web Data Connector URL and press Enter. It is to be noted that, Tableau will present you with an error message if you enter a Website URL instead of the Data Connector URL.
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- Step 3: The connector may show a web page asking for some information. Enter the required details and submit. It may take some time as the connector retrieves your data and imports it into Tableau as an extract.
- Step 4: Finally, click on the sheet tab to get started with your analysis.
To get a better sense of the Tableau WDC source, you can go through the following aspects:
1. Tableau Web Connector Data Source Example
Now that you have connected to the Tableau Web Data Connector, the connection page allows you to perform the following operations:
- You can check out the history of all connected web data connectors or clear the history from the drop-down list in the address bar.
- You can get a complete list of the five most recently used connectors under Recent Connectors
- For more information on the Web Data Connector, you can click on the following links at the bottom of the window:
- What is it? A link to an overview of this feature.
- Use a Connector link to this topic.
- Build a Connector is linked to the Web Data Connector SDK that provides you with tools and documentation for creating web data connectors.
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2. Configuring Additional / Optional Settings
After setting up a connection with the Tableau Web Data Connector, you can also customize and configure the following optional settings according to your individual use case:
- Sort Fields and Rows: You can choose how to sort your columns in the grid or the metadata grid from the list of options available in the Sort Fields drop-down list. To sort the row values, you can click on the sort button present next to the column name.
- Rename or hide columns: Click on the column header drop-down arrow and choose the option you want.
- Split columns: You can also split the columns in your data into new fields according to how the data is structured.
- Create calculations: Based on an existing field in the data source, you can create a new calculation.
- Copy values: To copy values in the grid, select the values and then press Ctrl+C. For copying values in the metadata grid, select the values, right-click, and then select Copy.
- Add new or edit other data sources: You can add or edit data sources by clicking on the drop-down arrow next to the data source.
How to Use Tableau Web Data Connector on Tableau Online and Tableau Server
Tableau creates an extract of the data that the web data connector accesses when you use it. Tableau Desktop allows you to refresh the extract. As an additional security feature, Tableau Server doesn’t allow you to refresh the extract until the web data connector is added to Tableau Server’s safe list.
When the connector requires you to provide credentials to sign in to the web-based data source, you need to make sure that the credentials are embedded with the data source.
After you have tested and validated the Tableau Web Data Connector, the server administrator can enter the connector’s URL into the server’s safe list. This URL should be provided by the server administrator to you and anyone else who wishes to use the connector in a workbook.
It may happen that you wish to open a workbook on Tableau Server that was built using a web data connector that was not present in the safe list on Tableau Server. For successfully refreshing the extract on Tableau Server, you can follow the process for testing, vetting, and adding the connector to the safe list.
When publishing to Tableau Online, it doesn’t allow you to connect or update extracts built by the Web Data Connector for security reasons. However, you can use Tableau Bridge to update some Web Data Connector extracts.
When publishing to Tableau Public, you can’t update the web data connector extract directly to Tableau Public as you can’t add a Web Data Connector to Tableau Public.
How can you Manage Connectors in a Safe List?
The Tableau Web Data Connector contains executable code and usually sends a request to a third-party website, so the Tableau Web Data Connector requires your consent. Before you can use WDC with Tableau Server, the domain and port used by the connector must be added to the safe list.
You also need to add the domain to which the connector can send and receive requests to the secondary safe list.
When you add a connector to the safelist, configure Tableau Server to allow connections to specific URLs that host the connector and from URLs that the connector can query. This is the only way to allow Tableau Server to run WDCs.
The connector can then be hosted on a server within your organization’s firewall or in an external domain. It is to be noted that Tableau Server does not support importing WDCs.
To effectively manage Tableau Web Data Connectors in your safe list, you can go through the following aspects:
1. Allowing or Disallowing WDC Extract Refreshes or WDCs
For allowing or disallowing Tableau Web Data Connectors, or WDC extract refreshes, you have to use the tsm data-access web-data-connectors allow command with the -t or -r options. By default, the WDCs and WDC extract refreshes are allowed. If you need to modify this setting, you have to execute the tsm pending-changes apply command.
2. Removing one or more WDCs from the Safe List
For removing one or more Tableau Web Data Connectors from your safe list, you can use the tsm data-access web-data-connectors delete command. For modifying this setting, you can execute the tsm pending-changes apply command.
3. Listing all WDCs on the Safe List
To view all the WDCs present on the safe list, you can use the tsm data-access web-data-connectors list command.
4. Adding Connectors to the Safe List and Secondary Safe List
You can easily add a connector to the safe list and secondary safe list, by running the tsm data-access web-data-connectors add command. This requires you to provide the name, safe list URL, and secondary safe list URLs.
You can also use the web-data-connector-settings Entity to manage Tableau Web Data Connectors. Once you have executed this command, you can apply your pending changes using the tsm pending-changes apply command.
You will get a message pop up on your screen warning you that the command will restart Tableau Server. If Tableau Server is currently running, it will restart, and if it is stopped, it will remain stopped without restarting.
tsm data-access web-data-connectors add --name "USGS Earthquakes" --url https://tableau.github.io:443/webdataconnector/Examples/html/earthquakeUSGS.html --secondary https://tableau.github.io/.*,https://earthquake.usgs.gov/.*,https://maxcdn.bootstrapcdn.com/.*,https://ajax.googleapis.com/.*,https://connectors.tableau.com/.*
While executing the commands discussed above, you can follow a set of guidelines given below for the best results:
- Make sure that you use straight quotes (” and `), not curly or “smart” quotes, around the name of the Tableau Web Data Connector. Also, use double quotes (“) if the name contains a space.
- For many Tableau Web Data Connectors, the port specified for the –url option is 443 or 80. However, you can examine the value for your connector by checking the data source details on Tableau Server. You must specify the port number as part of the URL if the Tableau Web Data Connector is using SSL (HTTPS). For instance, for using the default port for HTTPS, the URL might look like the following: https://sample.com:443/WDC/.
- If WDCs send requests to and receive data from multiple domains, you can use a comma-delimited list of URL for the –secondary option. It is to be noted that if you do not add a secondary list, all requests are allowed. For additional security, make sure to add a secondary list that specifies the domains that provide the libraries and sources the Tableau Web Data Connector needs access to.
- For adding an entire domain to the secondary safe list, end the domain URL with a wildcard expression. Use .* as the wildcard to indicate the entire domain, as in the following example: https://sample.com/.*.
Refreshing the Extract for a Tableau Web Data Connector
Tableau Server creates an extract from the data returned by the connector when a user creates a workbook that uses a Tableau Web Data Connector. When the user publishes the workbook, the publish process sends the workbook as well as the data extract to the server. Tableau can refresh a WDC-created extract in the same way that it can refresh any extract.
If the connector asks for credentials to access the web-based data source, make sure to embed the credentials with the data source and that the Tableau Web Data Connector is on the server’s safe list. This is due to the fact that the refresh can take place on a schedule or in another background context, and the server cannot prompt for credentials.
There is currently no way to re-authenticate a data source directly from Tableau Server. If the data source’s credentials expire or the workbook and data extract were published without embedding the credentials, the workbook and data extract must be published again with the new embedded credentials.
If the background process that executes the refresh operation fails, an alert and a log entry are generated to indicate the problem. Users will notice that the extract’s timestamp does not change. You can use the tsm data-access web-data-connectors allow -r false command to disable refresh for all WDCs.
Troubleshooting
You can look at the log files if the server has trouble adding connectors to the safe list. Check the log files on the first server node as well as the other nodes involved in the gateway operation. For more information on log files, Tableau Server Logs, and Log File Locations.
If you’re having trouble refreshing a WDC-created extract, make sure the webdataconnector.refresh.enabled configuration setting is set to true. Run the following command if it is set to false to allow extract refreshes for all WDCs on the server:
tsm data-access web-data-connectors allow -r true
Conclusion
In this article, you have learned how to effectively use the Tableau Web Data Connector. Tableau is a powerful Data Visualization Tool that allows you to gain important insights via stunning reports & dashboards. Tableau Web Data Connector allows you to connect to a website and extract data published in JSON, XML, or HTML. Setting up & managing Tableau Web Data Connector can be easily done by executing simple commands as discussed above.
As you collect and manage your data across several applications and databases in your business, it is important to consolidate it for a complete performance analysis of your business. However, it is a time-consuming and resource-intensive task to continuously monitor the Data Connectors. To achieve this efficiently, you need to assign a portion of your engineering bandwidth to Integrate data from all sources, Clean & Transform it, and finally, Load it to a Cloud Data Warehouse, BI Tool like Tableau, or a destination of your choice for further Business Analytics. All of these challenges can be comfortably solved by a Cloud-based ETL tool such as Hevo Data.
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Tell us about your experience of using the Tableau Web Data Connector! Share your thoughts with us in the comments section below.
Sanchit Agarwal is an Engineer turned Data Analyst with a passion for data, software architecture and AI. He leverages his diverse technical background and 2+ years of experience to write content. He has penned over 200 articles on data integration and infrastructures, driven by a desire to empower data practitioners with practical solutions for their everyday challenges.
