Unable to get Data from url using signal and following datasources are empty

[mathiastiberghien]

Hi,
I have issue when i try to load a data from url using signal reference.
Did I configure something wrong?
Thanks
Here's my sample: Vega Editor Sample

I you look in the data viewer:
"data_1": hard-coded values, have the expected data
"data_from_url": hard-coded url, have the expected data
"data_from_url_signal": url based on signal reference, data table is empty
"data_2": hard-coded values, data table is empty

if you add define datasources after "data_from_url_signal" the data remains empty
There are no logs indicating any failure

[roying]

An error is shown in the javascript console:

For data in JSON format, Vega expects an array of objects.
https://vega.github.io/vega/docs/data/

The data from the URL is in this format which is not what Vega expects:

{
	"cod": "200",
	"message": 0.0069,
	"cnt": 40,
	"list": [{
			"dt": 1568646000,
			"main": {
				"temp": 27.05,
				"temp_min": 26.3,
				"temp_max": 27.05,
				"pressure": 1019.99,
				"sea_level": 1019.99,
				"grnd_level": 1008.76,
				"humidity": 38,
				"temp_kf": 0.76
			},
			"weather": [{
					"id": 802,
					"main": "Clouds",
					"description": "scattered clouds",
					"icon": "03d"
				}
			],
			"clouds": {
				"all": 39
			},
			"wind": {
				"speed": 3.08,
				"deg": 317.028
			},
			"sys": {
				"pod": "d"
			},
			"dt_txt": "2019-09-16 15:00:00"
		}, {
			"dt": 1568656800,
...

The workaround is to use javascript to fetch data from the URL, process the data, and then replace the data in the Vega dataset using Vega View API:

   view.data(name[, values])

(Vega version ≥5.5) If two arguments are provided, removes the current data and inserts the input values, which can be either a single data object or an array of data objects.

https://vega.github.io/vega/docs/api/view/

[mathiastiberghien]

Thanks for the answer, I'll think to use the javascript debugger now (I'm new to Vega but really enjoy it)
But in my sample, I also defined a datasource with the same url than the one using scale, but this one doesn't fail even if the query return also one object.
I was expecting that the behavior should be the same using inline url or signal url: both failing or both succeeding

[jheer]

Thanks for sharing the issue! I agree that the two loading methods should behave similarly. I've made a minor adjustment to the Load operator in the vega-transforms package that will ensure any retrieved values are wrapped in an array if not already array-valued, such that behavior of built-in and dynamic URL loading are better aligned. This fix will be included in the next release.

[mathiastiberghien]

Great, thanks! I really enjoy your work by the way. The visualization grammar approach is awesome Le mar. 24 sept. 2019 à 10:56, Jeffrey Heer <notifications@github.com> a écrit :

…

Thanks for sharing the issue! I agree that the two loading methods should behave similarly. I've made a minor adjustment to the Load operator in the vega-transforms package that will ensure any retrieved values are wrapped in an array if not already array-valued, such that behavior of built-in and dynamic URL loading are better aligned. This fix will be included in the next release. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#2014?email_source=notifications&email_token=AFLNF7DRE73ORWXR4TQZWQ3QLHI4NA5CNFSM4IXCB5MKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD7NUA6A#issuecomment-534462584>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AFLNF7CJNFEYB4VREC6P7PLQLHI4NANCNFSM4IXCB5MA> .