Uploading a directory of images to couchdb

I wanted to have a general script to upload a set of images to couchdb. Couch can't store images as documents because it uses JSON for that. But you can still create a JSON document and attach a set of annotations to it in the form of images. But here's the catch: you have to specify the document's revision id, and that changes after every image you add.

But I had two problems. My directory of images contained sub-directories. I also wanted to access the images directly using a simple URL. So if I had a directory structure like:

    list
        file1.png
        one
            file2.png
            file3.png
        two
            file4.png

I would want the relative URLs to be: /list/file1.png and /list/one/file2.png etc. The trick in writing the script is to extract the revid from the server response. I used awk for that, then used the returned value to upload the next entry in that directory. The second trick is to use %2F not / as a directory separator when creating the docids. Couch doesn't allow nesting in the database structure but you can simulate it by creating documents called:

list
list%2Fone
line%2Ftwo

The first posting to each of those documents doesn't need a revid, but subsequent ones do. That's just a feature of couch. So here's the script. It's a bity sloppy because if couch responds with an error to any upload it will fall over. This bit of error-handling is currently left as an exercise to the reader. I'll put it in later and may update the post then. To use the script put it into a file called upload.sh and then invoke it thus: ./upload.sh images, where "images" is the master image directory.

#!/bin/bash contains() { echo `echo $1 | grep -c $2` } docid() { echo `echo $1 | awk '{gsub(/\//,"%2F",$1);print $1;}'` } filename() { echo `echo $1 | awk '{l=split($1,a,"/");print a[l];}'` } upload() { local REVEXPR="" if [ $3 ]; then REVEXPR="?rev=$3" fi local FILENAME=`filename $f` local RESPONSE=`curl -X PUT http://user:password@localhost:5984/corpix/$1/$FILENAME$REVEXPR --data-binary @$2 -H "Content-Type: image/png"` echo `echo $RESPONSE | awk '{split($1,a,"\"");print a[10]}'` } descend() { local DIR=$1 local REVID="" local DOCID=`docid $DIR` for f in $DIR/* do if [ -d $f ]; then descend $f elif [ -f $f ]; then local CONTAINS=`contains $f ".png"` if [ $CONTAINS = 1 ]; then REVID=`upload $DOCID $f $REVID` fi fi done } descend $1