Variable for csv filename in pull-data

[nancyv]

Can a variable be used for the csv filename for pulldata?
When I use this (with variable fileName previously defined in survey):
pulldata(${fileName}, ‘plot_type’,‘plotid_key’,${PlotID})

the form deploys but gives the error ‘Failed to fetch’ when opened as though it doesn’t have the proper CSV filename.

However, it works without problem if I change it to use the static filename as in:
pulldata(‘myCsvFile’, ‘plot_type’,‘plotid_key’,${PlotID})

So, the csv file is not a problem, is properly formatted, can be loaded, and read.

I want to do this because I have 2 different csv files and which one I want to pull data from depends on a previous answer in my survey.

[wroos]

Welcome @nancyv,
Can you

• check with a text variable or note what the ${filename} is
• try to put it between ’ …’ or " … " in the pulldata function

[nancyv]

Thank you @wroos.

Yes, I have done both of those things:

• The ${filename} variable is the name of the file (without the .csv extension - the same string that when put literally in the pulldata function works just fine).

• Adding single (’…’) or double ("…") quotes in the pulldata function itself as in pulldata(’${filename}’,… or pulldata("${filename}",… results in the same ‘Failed to fetch’ error.

(Sorry, can’t attach example survey spreadsheet and data file because I am ‘new user’).

[wroos]

Hello @nancyv,
maybe @Kal_Lam can take over, please?

You might try with

• pulldata( concat("’", ${filename}, “’”) ), … ), i.e. " ’ "
• pulldata( jr://file-csv/path/to/${filename}.csv, …)

[nancyv]

Ok thanks for the suggestions.

The first suggestion did not work. I tried it with single apostrophes (not ‘smart quote’ - right?)

The second suggestion didn’t work either but I am not sure I have the syntax correct. Where is the documentation on this?
I tried ‘pulldata( jr://file-csv/${filename}.csv, …)’ as I am not sure what the proper ‘path/to’ would be. My file lives in the ‘Media’ folder…
And, is concat not required as in:
pulldata(concat(‘jr://file-csv/’,${filename},’.csv’, …) or something similar?

Is this not a bug/issue where 'pulldatat(${filename}, …) isn’t being interpreted correctly? Can someone examine what is getting generated by the XLSForm to XForm converter from a simple example as in here ( I can provide a simple example when allowed by forum):

Calculation on repeat inside another repeat

[wroos]

Hello @nancyv,
here are the links
https://getodk.github.io/xforms-spec/#fn:pulldata
https://getodk.github.io/xforms-spec/#file-endpoints

You might

• use your form and print it as pdf to see how ${filename} is replaced
• show $filename}.in a note (or a textfield)
• try another name, e.g. MyFileName

[Josh]

Hi @nancyv, @wroos, this is related to the discussion here about trying to include images dynamically.

How to Pulldata Images

Hi @dedik2urniawan, I think this approach might not work as expected since Enketo pulls referenced images on page loading (at least in my testing). An alternative approach could be to do something like this: If you have four images, blue_pill.png, red_pill.png, blue_ball.png and red_ball.png then you can display them variably with a relevant condition: survey type name label relevant media::image calculation select_one colours colour Colour select_one objects object Object c…

Unfortunately, Enketo resolves the URLs (jr://...) on the backend and fetches the external data when the form is first loaded — therefore it needs to know the filename upfront. You can see this difference in the XML of the XLSForm, one with a dynamic filename and one fixed (example from the XLSForm docs on pulldata):

survey 1

type	name	label	calculation
calculate	filename		‘fruits’
calculate	fruit		pulldata(${filename}, ‘name’, ‘name_key’, ‘mango’)
note	note_country	The fruit ${fruit} is pulled csv data.

survey 2

type	name	label	calculation
calculate	fruit		pulldata(‘fruits’, ‘name’, ‘name_key’, ‘mango’)
note	note_country	The fruit ${fruit} is pulled csv data.

@@ -14,10 +14,10 @@
           </meta>
         </aUJ4gsohDFa8wmxGiSs5Dg>
       </instance>
-      <instance id="${filename}" src="jr://file-csv/${filename}.csv"/>
+      <instance id="fruits" src="jr://file-csv/fruits.csv"/>
       <bind calculate="'fruits'" nodeset="/aUJ4gsohDFa8wmxGiSs5Dg/filename" type="string"/>
       <bind nodeset="/aUJ4gsohDFa8wmxGiSs5Dg/n" readonly="true()" type="string"/>
-      <bind calculate="pulldata( /aUJ4gsohDFa8wmxGiSs5Dg/filename , 'name', 'name_key', 'mango')" nodeset="/aUJ4gsohDFa8wmxGiSs5Dg/fruit" type="string"/>
+      <bind calculate="pulldata('fruits', 'name', 'name_key', 'mango')" nodeset="/aUJ4gsohDFa8wmxGiSs5Dg/fruit" type="string"/>
       <bind nodeset="/aUJ4gsohDFa8wmxGiSs5Dg/note_country" readonly="true()" type="string"/>
       <bind jr:preload="uid" nodeset="/aUJ4gsohDFa8wmxGiSs5Dg/meta/instanceID" readonly="true()" type="string"/>
     </model>

In the network tab of your browser’s dev tools, you can see that the form with a dynamic filename does not make a GET request for the data, but when the filename is declared upfront you can see:

Additionally, you can see the difference in how Enketo resolves these URLs in the response to the POST request made to /transform/xform:

@@ -14,5 +14,5 @@
             </meta>
         </aUJ4gsohDFa8wmxGiSs5Dg>
     </instance>
-    <instance id="${filename}" src="jr://file-csv/${filename}.csv"/>
+    <instance id="fruits" src="/media/get/https/kc.kobotoolbox.org/joshuaberetta/xformsMedia/970740/1564798.csv"/>
 </model>

So in summary, you will have to do something similar to what I recommended in the linked thread where you load all external data and then reference it inside the form in a dynamic way. Hope that helps

[nancyv]

Thank you @josh. You are correct that this does not work in Enketo and I have now been able to see that in the xml of the XLSForm. @wroos - it doesn’t matter what format used for the first arg of pulldata, it is used without translation.

I have worked around this for now using ‘if’ statements to pull from different files as suggested here:

Pull Data with If Condition from 2 external Files

Hi @Kal_Lam Can you please guide , how can we create pull data condition from 2 external file with if condition. we have 2 external files recoveryupload odupload Please help to correct the below if condition if Field Name - work_type is equal to ‘regular_repayment_visit’, then pulldata(‘recoveryupload’,‘state’,‘memloanid’,${Loanid} else pulldata(‘odupload’,‘state’,‘memloanid’,${Loanid} Cheers ! Neeraj

This is really a workaround and not a solution as what I was looking for was a way to have my filename be set by default to a variable so I could easily change filenames. With this workaround, I still have the filename hardcoded in multiple/many places in my form.

I thought I saw elsewhere in the specs that variables could be used for all the args to pulldata…
Even if preloading, it seems that could be possible with a variable that is given a default value in the form (ie one that is not dependent upon user input).

BTW, I am not seeing /transform/xform in Chrome dev tools. Is this on form load?