[Q&A]: Error with `read.csv`

jonathan-taylor commented 8 months ago

What's your question?

I am unable to download files that I know are publicly readable example

read.csv('https://web.stanford.edu/class/stats191/data/schizophrenia.csv', header=TRUE)

I get an error like:

Access to XMLHttpRequest at 'https://www.stanford.edu/class/stats191/data/schizophrenia.csv' from origin 'null' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

Is there a config I need to set for this request so that the server doesn't think it's "null"?

jonathan-taylor commented 8 months ago

Error above is in the JavaScript console.... doesn't appear in the HTML seen in the page.

coatless commented 8 months ago

Yup, the server in this case needs to enable Cross-origin resource sharing (CORS).

Assuming the server is using nginx, you can enable it just for data files with:

location ~* \.(csv|xls|txt)$ {
    add_header Access-Control-Allow-Origin *;
}

Or enable it globally across all files with:

location / {
    add_header 'Access-Control-Allow-Origin' '*' always;
}

The quickest way forward is to create a data-raw repo on GitHub and enable GitHub Pages as CORS is on by default, c.f.

https://github.com/coatless/raw-data

https://coatless.github.io/raw-data/

jonathan-taylor commented 8 months ago

Thanks, made a github repo for data files. Works fine

From: James J Balamuta @.> Sent: Wednesday, March 27, 2024 10:32 PM To: coatless/quarto-webr @.> Cc: Jonathan Taylor @.>; Author @.> Subject: Re: [coatless/quarto-webr] [Q&A]: Error with read.csv (Issue #174)

Yup, the server in this case needs to enable Cross-origin resource sharing (CORS):

You can enable it just for data files with:

location ~ .(csv|xls|txt)$ { add_header Access-Control-Allow-Origin ; }

Or enable it globally with:

location / { add_header 'Access-Control-Allow-Origin' '*' always; }

Perhaps the easiest way forward is to create a data-raw repo on GitHub and enable GitHub Pages as CORS is on by default, c.f.

https://github.com/coatless/raw-data

https://coatless.github.io/raw-data/

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coatless / quarto-webr

[Q&A]: Error with `read.csv` #174

What's your question?