Just trying to download a file from a website.... this should be easy

Help Activities
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Hi team,

long-time listener. first-time caller.

Anyway, knowing me, I am doing something obvious and stupid. But it is nonetheless causing me some struggles.

All I am trying to do is download a file from a website. The website can be found here and if you look about half way down the page, there is a place you can click to “download a CSV file”.

I would have thought that this would be a very straight forward thing to do in UiPath, but apparently not. At least not any of the methods I have tried.

Wget

The first approach I tried was using Wget and a command prompt using the basic approach in this video from 3 years ago. It sort of worked but only if I open the command prompt first. Otherwise, it went through the motions but didn’t succeed.

I suspect that as UiPath has gone through a number of iterations since the video i used was created and the process is different now. But I have no idea what I’m missing. Its obviously some kind of “open first” commence or something, but I can’t find it.

The attached zip file DomainListWget.zip will work (sorta). All you should need to do to get it working is change the variable “DownloadPath” to be a folder on your PC and it should work.

DomainListWget.zip (203.7 KB)

PowerShell Cmdlet

Ok this one I really don’t get. Based on what I can find on the internet here this seems pretty straight forward. And yet it doesn’t work!

All I am trying to do is execute the following command which works perfectly if I issue it from PowerShell.

Invoke-WebRequest -URI https://f.hubspotusercontent40.net/hubfs/2832391/Marketing/Lead-Capture/free-domains-2.csv -OutFile E:\source\RPA\helpers\free-domains-2.csv

However if I try to invoke it with UiPath, I get the following error. Unfortunately, I am not that familiar with UiPath and in particular this process to work out why its not working.

ERROR Validation Error Internal constraint exception while running constraint with name ‘Constraint’ against activity of type System.Activities.Statements.Sequence with name ‘Sequence’. Exception was: System.NullReferenceException: Object reference not set to an instance of an object.
at System.Activities.WorkflowApplication.Invoke(Activity activity, IDictionary2 inputs, WorkflowInstanceExtensionManager extensions, TimeSpan timeout) at System.Activities.WorkflowInvoker.Invoke(Activity workflow, IDictionary2 inputs)
at System.Activities.Validation.ActivityValidationServices.RunConstraints(ChildActivity childActivity, ActivityCallStack parentChain, IList`1 constraints, ProcessActivityTreeOptions

the UiPath file can be found in this zipfile
DomainListPSCmdLet.zip (145.4 KB)

PowerShell script

Again, I don’t get why this isn’t working. After my failures using a Cmdlet I thought, ok lets try a script.

So I wrote this script.

param ($WebURL, $SavePath)

#Invoke-WebRequest

Invoke-WebRequest -URI https://f.hubspotusercontent40.net/hubfs/2832391/Marketing/Lead-Capture/free-domains-2.csv -OutFile $SavePath

i then saved it as GetCSV.ps1

When you invoke it using PowerShell you use the following command.

.\GetCSV.ps1 -WebURL <URL> -SavePath <path>

Which translates too in my case.

.\GetCSV.ps1 -WebURL ='https://f.hubspotusercontent40.net/hubfs/2832391/Marketing/Lead-Capture/free-domains-2.csv' -SavePath "E:\source\RPA\helpers\free-domains-2.csv"

It works perfectly in PowerShell. But in UiPath I get the following error.

ERROR Validation Error Internal constraint exception while running constraint with name ‘Constraint’ against activity of type System.Activities.Statements.Sequence with name ‘Sequence’. Exception was: System.NullReferenceException: Object reference not set to an instance of an object.
at System.Activities.WorkflowApplication.Invoke(Activity activity, IDictionary2 inputs, WorkflowInstanceExtensionManager extensions, TimeSpan timeout) at System.Activities.WorkflowInvoker.Invoke(Activity workflow, IDictionary2 inputs)
at System.Activities.Validation.ActivityValidationServices.RunConstraints(ChildActivity childActivity, ActivityCallStack parentChain, IList1 constraints, ProcessActivityTreeOptions options, Boolean suppressGetChildrenViolations, IList1& validationErrors) Main.xaml

as this is the same error, it seems that it is configuration related, and it is possibly related to the “typeArgument” but I havnt been able to understand what this actualy dose. Again because I am relatively new to UiPath

the UiPath file can be found in this zipfile
DomainListPowerShell.zip (165.5 KB)

thanks in advance for your help.

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@Coffeesnob

You need to follow the steps below

  1. Use open browser or use application/browser and navigate to the required url…

  2. Then use get attribute with the selector of download a csv file and select the attribute name as href and save it to a string which gives you the url to file

  3. Now use http request activity(downlod UiPath.webapi.activities if not found ) and pass the string output feom strp 2 to request uri field in http request and assign a filelocation to file name for response attachment and the file would be saved

Cheers

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Hi @Coffeesnob,

That is not a good first impression of UiPath. Lets try and fix that :slight_smile:
I have a suggestion which can help you here without using Invoke PowerShell activity (until it is fixed)

Why did Invoke PowerShell not work though?

Unfortunately your dive into UiPath coincides with a recent update in UiPath Studio which has rendered Invoke Powershell useless. Read more here : UiPath Community 2022.12 Release - #41 by jeevith

You can use any one of these:

  1. Start Process - Easy to reuse what you already have
    Now to Start Process a beast of a activity in Studio. This can do a lot.

    image
    image1236×363 26.9 KB

    As arguments to start process I provide a string and some string manipulation to set the path of the target file
    "Invoke-WebRequest -URI https://f.hubspotusercontent40.net/hubfs/2832391/Marketing/Lead-Capture/free-domains-2.csv -OutFile OUTPUT".Replace("OUTPUT", Path.Join(Environment.CurrentDirectory, "free-domains-2.csv"))
    Other alternative activities

  2. HTTP Request
    You can also download files using the HTTP Request activity with a GET operation. This requires additional package from Manage Packages → Official → UiPath.WebAPI.Activities

    image
    image892×469 26.4 KB

  3. Inject Javascript
    You can use this activity to Inject a Javascript function when your browser is open. It will work just like the two above.

  4. Invoke Powershell (Which you tried already)

  5. Invoke code (you can chose Vb or c# to download files)

I have commented out the rest of the workflow. The target file will be downloaded in the project folder. Hope this helps!
SolutionDomainListPowerShell.zip (9.0 KB)

2 Likes
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@jeevith wow man, thanks so much, you realy went the extra mile in explaining this, I realy apreciate it thank you.

1 Like
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@Anil_G thanks for the sugestions. I will give it a shot.

1 Like
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