Reading CSV files about arangodb HOT 9 CLOSED

I would really like to see something like this:

while the csv and json importers are useful, they are not generic enough to import arbitrary data: I was playing around recently and wanted to do a bulk import of data, roughly 2GB. It would be nice to be able to load and process such a file immediately from within arango, but the File.read function in the fs module (is this module even officially there? I had to dig around quite a lot to find it) will always read the entire file.

It would be great to have a more versatile read that can be provided length or buffers or callbacks. This way the import tools can be rewritten in arango directly (I think I recall the json and csv importer imported via the http API?)

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I pre-process my raw data to csv and then use the importer. Works fine. ;) What would the benefit be from moving this to ArangoDb?

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Hi, would like to chime in, but I am not sure what you mean by "What would the benefit be from moving this to ArangoDb?" 😄 Can you elaborate, on what you want to do, what you did, and what the last sentence means? 😃

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Hi Frank,

If I understood correctly, @a2800276 wants to be able to process his raw data and enter them into the db from withing arangosh.

I was wandering why the devs should invest time to this feature since one can easily process his raw data into csv/json (via any language, say PHP or Python, or Bash) and use the already working importer.

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Oh, yes, didn't notice the different users 😄 . Yes of course, I totally agree with @rotatingJazz on that.
@a2800276 is there some specific reason not to use the import? Is there some edge case that you're trying to tackle?
I have had no issues for importing external data, so far, so I am interested in your edge case 😄

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I pre-process my raw data to csv and then use the importer.

To me it seems very elaborate to preprocess data, that may or may not be in a form suitable for CSV/JSON, transforming it to a different format, throwing that against a --functionally restricted-- import script which then uses HTTP to import individual records to the database.

When instead:

I could be reading and transforming arbitrarily formatted files from within DB and have a much more efficient workflow, both from the "programmer efficiency" point of view and in terms of performance.

What I was trying to do concretely:

re-implement a toy project to play with graph functionality that I have working for neo4j in arango. I'd like to importethe wikipedia inter-page links and play around with that dataset. The dump of that data is 4GB, (in the form of mysql INSERT statements). If I can avoid it, I don't want to preprocess 4GB of data into 3GB of some other data that I can import when I could import directly in ~half the time.

More generally:

Since arango wants to become a general purpose deployment platform with Foxx, then it will certainly need some rudimentary file io implementation. As it's currently implemented, File.read is utterly useless apart from reading tiny toy files.

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It might be interesting to have some reference data that one could try to
'feel' or confirm the problem with the current importer; maybe the problem
can be shown with similar data from here e.g:

• http://www.imdb.com/interfaces (movies, actors, ...?)
• http://www.datawrangling.com/some-datasets-available-on-the-web

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We'll eventually have an implementation of Buffer, which will allow us to read binary files and process them in chunks from JavaScript.

Until that's available, I think there are two alternatives available at least for processing CSV and JSON files.
They should work incrementally and process the input file line-wise (not quite true for CSV but think of them as working line-wise). They allow supplying a callback function that is executed whenever a record was read. You can then use the callback to process the data and put it into the database.

Example invocation for CSV files:

var internal = require("internal");
// var options = { separator: ",", quote: "\"" };
internal.processCsvFile("test.csv", function (data) { internal.print(data); }, options );

And for p```
var internal = require("internal");
internal.processCsvFile("test.csv", function (data) { internal.print(data); } );

Processing JSON files is similar:

var internal = require("internal");
internal.processJsonFile("test.json", function (data) { internal.print(data); } );

Note that the above function aren't general purpose file-processing functions, but targeted for handling UTF-8 encoded CSV and JSON data. 
For arbitrary file formats, we'll need an implementation of Buffer in Javascript.

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Closed because processCsvFile and processJsonFile are doing what I intended.

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