Hello all, I'm just about to start on my first (wildly ambitious) Couchapp. I've had quite a bit of Erlang experience, but not for the past couple of years so I'm a bit rusty. I've had a tiny bit of experience with CouchDB via various Python scripts, but that's all been treating CouchDB as a "black box" database so I've currently got little knowledge of what it can do beyond being a document datastore.
Initially, I'm trying to understand my options for uploading CSV files, parsing out the content and storing them in CouchDB (one CouchDB record per line of CSV content). While it's reasonably straightforward to do this if I was using e.g. Python as a batch load tool, I don't want to go outside Javascript for this project if I can avoid it. The CSV files are anywhere from 1k-30k records, with 8-10 fields in each that are straightforward timestamps and floating point numbers. For an old-school Web app with distinct database and app server layers, there's a straightforward option - upload the data to a file on the web server, then process the data out of the file and load it into your database. Sure there's variations on this approach such as saving data as a database blob, but I'm looking for the best CouchApp-specific approach if one exists. Options I can see: - upload the data & save it into a single "uploaded_csv" document in CouchDB. Within CouchDB, detect the presence of a new "uploaded_csv" document, extract and process the content using Javascript and save it into multiple "data" records, with appropriate indexing, then dispose of the "uploaded_csv" document or mark it as "processed". This seems reasonably straightforward, but I'm not sure how to detect the presence of a new "uploaded_csv" document (is there a cron equivalent in Couch?) and I'd have to track the progress of processing each uploaded CSV file to detect when they've been processed into "data" records - upload the data & save it into a single "uploaded_csv" document in CouchDB. Have CouchDB running embedded in an Erlang app, and use Erlang to read the "uploaded_csv" data, then send a series of e.g. HTTP PUTs to load the data into multiple "data" records in CouchDB. This just seems ugly to me, but I'm pretty confident I could get it working pretty easily - upload the data and process it directly into "data" records from a web page served from CouchApp. This seems like it could impact on scalability due to having long-running connections between client and server, but at least a user would know when their data has been uploaded and processed successfully with trivial extra work on my part - upload the data, convert it to JSON on the client using clientside Javascript, then send it as a set of document uploads (i.e. one document per CSV record) from the client to the Couch server. This would let me parse out any bogus CSV content without sending it to the server, but I'll have users running browsers on mobile devices and I'm not sure I want to put that processing load onto the client Are there any "recommended" approaches for this type of task? I suspect this question and others I'll ask have probably already been considered and dealt with by various experts; if there's a "CouchApp cookbook" with recommended solutions for these and other common situations, I'd appreciate a pointer to it so I could start to answer my own questions. Thanks in advance Dave M.
