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I've been meaning to learn jq, so I decided to give it a try. FRUITS=$(cat input.json | jq '.models | map(select(.title == "fruits")) | .[0]') FRUIT_NA

I've been meaning to learn jq, so I decided to give it a try. FRUITS=$(cat input.json | jq '.models | map(select(.title == "fruits")) | .[0]') FRUIT_NAME_KEY=$(echo "$FRUITS" | jq '.fields | map(select(.name == "Name")) | .[0].key') FARMERS=$(cat input.json | jq '.models | map(select(.title == "farmers")) | .[0]') FARMER_NAME_KEY=$(echo "$FARMERS" | jq '.fields | map(select(.name == "Full name")) | .[0].key') FARMER_FRUITS_KEY=$(echo "$FARMERS" | jq '.fields | map(select(.name == "Fruits")) | .[0].key') BOB=$(echo "$FARMERS" | jq '.entities | map(select(.['$FARMER_NAME_KEY'] == "Bob, the farmer")) | .[0]') BOB_FRUIT_IDS=$(echo "$BOB" | jq '.['$FARMER_FRUITS_KEY'] | .[]' -r) for BOB_FRUIT_ID in "$BOB_FRUIT_IDS"; do echo "$FRUITS" | jq '.entities | map(select(._id == "'$BOB_FRUIT_ID'")) | .[0] | .['$FRUIT_NAME_KEY']' done There's a bit of bash boilerplate, but honestly it was about what I would expect, given a structure with so many layers of indirection. Pain points: * Switching between bash and jq's filtering language led me to use string interpolation with bash variables. Malicious inputs can probably exploit this (and it was just awkward anyway). * A "select one" filter would be nice, instead of select + get first element.

andolanra 10y ago
jq is powerful enough to express it in one query: it has variables (using expr as name) which make this thing at least vaguely feasible. That doesn't mean you should, but you could: .models | (.[] | if .title == "farmers" then (.fields | .[] | if .name == "Fruits" then .key else empty end) as $fruits | (.fields | .[] | if .name == "Full name" then .key else empty end) as $name | .entities | .[] | if .[ $name ] == "Bob, the farmer" then .[ $fruits ] else empty end else empty end) as $fruits | .[] | if .["title"] == "fruits" then ( .fields | .[] | if .name == "Name" then .key else empty end) as $fruit_name | .entities | [ .[] | {(._id): .[$fruit_name]} ] | add as $lookup | $fruits | .[] | $lookup[.] else empty end (I'm not claiming this is the best way to write that query, but it's the first one I came up with.)
davvid 10y ago
Here's the equivalent using jsonaxe[1]. The main difference is the python-like syntax, which is either good or bad depending on your tastes. The pain point about string interpolation remains, tho. data=input.json fruits () { jsonaxe 'models.filter(lambda x: x["title"] == "fruits")[0]' "$data" } farmers () { jsonaxe 'models.filter(lambda x: x["title"] == "farmers")[0]' "$data" } fruit_name_key=$(fruits | jsonaxe --raw 'fields.filter(lambda x: x["name"] == "Name")[0].key') farmer_name_key=$(farmers | jsonaxe --raw 'fields.filter(lambda x: x["name"] == "Full name")[0].key') farmer_fruits_key=$(farmers | jsonaxe --raw 'fields.filter(lambda x: x["name"] == "Fruits")[0].key') farmers | # get bob jsonaxe "entities.filter(lambda x: x['$farmer_name_key'] == 'Bob, the farmer')[0]" | # get bob's fruits key jsonaxe --raw "get('$farmer_fruits_key')" | while read fruit_id do fruits | jsonaxe "entities.filter(lambda x: x['_id'] == '$fruit_id')[0]" | jsonaxe "get('$fruit_name_key')" done [1] https://github.com/davvid/jsonaxe https://github.com/davvid/jsonaxe

andolanra 10y ago

jq is powerful enough to express it in one query: it has variables (using expr as name) which make this thing at least vaguely feasible. That doesn't mean you should, but you could: .models | (.[] | if .title == "farmers" then (.fields | .[] | if .name == "Fruits" then .key else empty end) as $fruits | (.fields | .[] | if .name == "Full name" then .key else empty end) as $name | .entities | .[] | if .[ $name ] == "Bob, the farmer" then .[ $fruits ] else empty end else empty end) as $fruits | .[] | if .["title"] == "fruits" then ( .fields | .[] | if .name == "Name" then .key else empty end) as $fruit_name | .entities | [ .[] | {(._id): .[$fruit_name]} ] | add as $lookup | $fruits | .[] | $lookup[.] else empty end (I'm not claiming this is the best way to write that query, but it's the first one I came up with.)

davvid 10y ago

Here's the equivalent using jsonaxe[1]. The main difference is the python-like syntax, which is either good or bad depending on your tastes. The pain point about string interpolation remains, tho. data=input.json fruits () { jsonaxe 'models.filter(lambda x: x["title"] == "fruits")[0]' "$data" } farmers () { jsonaxe 'models.filter(lambda x: x["title"] == "farmers")[0]' "$data" } fruit_name_key=$(fruits | jsonaxe --raw 'fields.filter(lambda x: x["name"] == "Name")[0].key') farmer_name_key=$(farmers | jsonaxe --raw 'fields.filter(lambda x: x["name"] == "Full name")[0].key') farmer_fruits_key=$(farmers | jsonaxe --raw 'fields.filter(lambda x: x["name"] == "Fruits")[0].key') farmers | # get bob jsonaxe "entities.filter(lambda x: x['$farmer_name_key'] == 'Bob, the farmer')[0]" | # get bob's fruits key jsonaxe --raw "get('$farmer_fruits_key')" | while read fruit_id do fruits | jsonaxe "entities.filter(lambda x: x['_id'] == '$fruit_id')[0]" | jsonaxe "get('$fruit_name_key')" done [1] https://github.com/davvid/jsonaxe https://github.com/davvid/jsonaxe