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Helper I
Helper I

Use a Custom Connector to get data from flat file

Hi everyone,


I'm looking for alternatives for overcoming the infamous "FIREWALL ERROR" when refreshing a report that merges both on premises and web contents in mashup stage, like loading a file and then calling a function with a dynamic Url for each row. Well, for my cases until now I ignored the privacy levels and used the Personal Gateway to enable Fast Combine during refreshes, but I was wondering if I could somehow overcome this in a "more legit way" by creating a Custom Connector where the user inputs a file path and the script does the rest. I know there is the OleDb.Datasource() function that in theory should connect to flat files (I guess), but I couldn't make it work, neither I've found a tutorial or sample about it. 


So, what I'm asking is to know if this is really possible to do, and if not, if there's some other approach to this kind of problem, that doesn't involve using the Personal Gateway, but the Enterprise one.

Community Support
Community Support

Hi @fdanielsouza 

I'm afraid there is no such method like creating a customer connector which can skip all other steps including configuring gateway with data sources.


Do you configure schedule refresh for the dataset? if you use it, after first steup, there is no need to set anything manually.


Best Regards
Community Support Team _ Maggie Li
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.



Thank you for the answer, but what I'm looking for is not to create a custom connector that configure the Gateway itself, I know that this is not possible. I want to know is if it's possible to connect to a flat file using a custom connector, and if so, if someone can help me with a quick tutorial. 


My reason on this matter is that when you combine on prem and web data on Power Query (like calling an API for each row in a field), you need to enable Fast Combine, otherwise you get a "Firewall.Formula" error. And in order for these queries to be refreshed in Power BI Service, you also need to enable Fast Combine in the Gateway, but this option only exists for the Personal Gateway. So if I use the Enterprise Gateway there's no way to refresh the report on the service.


So, my idea was around building a custom connector that get flat file data and then get the web data based on the data in the file. which I could finally refresh using the Enterprise Gateway, because Fast Combine option wouldn't be needed, since Power Query would see only one data source (the custom connector).

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