FIWARE Orion: use query string in subscription payload - fiware-orion

Question

Currently the '=' sign is forbidden in Orion:
http://fiware-orion.readthedocs.io/en/1.5.0/user/forbidden_characters/index.html
But this prevents to make a subscription with a query string:
$ (curl broker.waziup.io/v1/subscribeContext -s -S --header 'Content-Type: application/json' \
--header 'Accept: application/json' --header 'Fiware-Service:waziup' --header 'Fiware-ServicePath:/TEST' -d #- | python -mjson.tool) <<EOF
{
"entities": [
{
"type": "SensingDevice",
"isPattern": "false",
"id": "Sensor1"
}
],
"attributes": [
"temperature"
],
"reference": "http://localhost/v1/sms/send?contact=0039&msg=Sensor1",
"duration": "P1M",
"notifyConditions": [
{
"type": "ONCHANGE",
"condValues": [
"temperature"
]
}
],
"throttling": "PT1S"
}
EOF
Results in:
{
"subscribeError": {
"errorCode": {
"code": "400",
"details": "Illegal value for JSON field",
"reasonPhrase": "Bad Request"
}
}
}
The query string is used to pass parameters to the callback server (I don't see other ways to do it).
Any way around this?

Answer 1

There is a way of setting query parameters in the notification URL, based in custom notifications in NGSIv2. Have a look to "Custom Notifications" section in the NGSIv2 specification.
The subscription you are doing would be something like this:
POST /v2/subscriptions
...
{
"subject": {
"entities": [
{
"id": "Sensor1",
"type": "SensingDevice"
}
],
"condition": {
"attrs": [ "temperature" ]
}
},
"notification": {
"httpCustom": {
"url": "http://localhost/v1/sms/send",
"qs": {
"contact": "0039",
"msg": "Sensor1"
}
},
"attrs": [ "temperature"]
},
"expires": "2016-05-07T18:30:00.00Z",
"throttling": 1
}
Note that you could even generalize the subscriptions for all your sensors using templates, in the following way:
POST /v2/subscriptions
...
{
"subject": {
"entities": [
{
"idPattern": "Sensor.*",
"type": "SensingDevice"
}
],
"condition": {
"attrs": [ "temperature" ]
}
},
"notification": {
"httpCustom": {
"url": "http://localhost/v1/sms/send",
"qs": {
"contact": "0039",
"msg": "${id}"
}
},
"attrs": [ "temperature"]
},
"expires": "2016-05-07T18:30:00.00Z",
"throttling": 1
}