Inputs.file & DuckDB

Community Help
1

Hi,

I wanted in a notebook to show how duckdb works with observablehq. Standard approach based on observable documentation works fine:

db = DuckDBClient.of({
  match : FileAttachment("example.csv")
})

after attaching the file. However, I wanted allow users to attach a file from disk based on Inputs.file. My code is

viewof csvfile = Inputs.file({label: "CSV file", accept: ".csv", required: true})

db_input = DuckDBClient.of({
  match : FileAttachment(csvfile["name"])
})

this gives me the following error:

image
image1199×804 31 KB

Is there a workaround ?

Reproducible example here

2

Maybe try this:

db_input = DuckDBClient.of({match: await csvfile.csv()})

1 Like
3

Thanks for the reply ! Worked like a charm !

1 Like
4

It seems to me that this first convert the csv stream to a JS array, which is further loaded by DuckDB. So the specific DuckDB velocity when dealing with (parsing) CSV files is probably shunted?
Likewise, a semicolon delimiter won’t be automatically recognized, although it is with FileAttachment().

I guess that the DuckDBClient needs to now the file’s type (.csv), which it can guess from the filename extension in “FileAttachement”, but not from the Input.file stream

5

I’d eventually suggest (upon scanning DuckDbClient.js code):
db_input = DuckDBClient.of({
match : {
file : Object.assign(csvfile, {mimeType:‘text/csv’}),
//delim: ‘;’ // to specify if <> ‘,’
}
})

1 Like