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This is good example of how we can Eliminate bottlenecks with IguanaX by building a custom file reader component which has a simple interface for a unique purpose rather than using a general purpose no code solution - see The problem with no-code solutions.

Here’s a scenario:

A large lab needs to have a file reading component which can feed files from different customers based on the prefix of the file, i.e. some files start with JJ99, others XYZ etc. depending on the source.

Let’s do it!

 Use +From URL to import a custom version of the file reader component for this tutorial

This component generates some test files to make it easier to learn how to make a custom file reader.

You can useCreate component +FROM URL to import the component.

Copy paste the URL from here:

git@bitbucket.org:interfaceware/file_tutorial.git
 Click on the Customize then the Copy and Edit button so you can access the Translator and alter the code

Refer to Customizing components to see how it's done if you have not done this before.

 Examine the Custom Field configurations in the component in config.json

To simplify the tutorial we have set these up a ClientList with the filename prefix Ids. Click on the config.json and you should see:

See Custom Fields to understand how this was created.

 Click on MatchRules.lua in the Project Tree to see where we need to alter the code

Navigate to MatchRules.lua in the Project Tree. This is the function we need to alter:

function MatchFile(FileName)
   return true
end

The file reader component is deliberately simple and uses /wiki/spaces/IXB/pages/3181903910 to make it more obvious how to modify the code to meet new needs. We need this function to return true when the matching criteria are met.

 Let's extract the filename using FILfilename() from the FIL Library, so we can look at it:

Change the matching to add in two lines so we can see the filenames we need to filter on.

function MatchFile(FileName)
   local JustFileName = FILfilename(FileName)
   trace(JustFileName)
   return true
end

These are the concepts we have used:

 Edit MatchRules.lua to extract the prefixes from the custom fields

Create a second function, APPidList() to extract the ClientList prefixes from the custom fields and update MatchFile() to call APPidList().

You can replace the contents of the MatchRules.lua file with this new code:

function APPidList()
   local IdList = component.fields()["ClientList"]
   return IdList
end

function MatchFile(FileName)
   local IdList = APPidList()
   trace(IdList)
   local JustFileName = FILfilename(FileName)
   trace(JustFileName)
   return true
end

Concepts used:

 Break the comma delimited string into a list to get each prefix Id

We can quickly do this by adding one line to AppidList( ) after line 2:

IdList = IdList:split(",")

You should see something like:

Concepts used:

 Make a matching function which takes the prefix and sees if the filename starts with it

Create a third function, APPmatchPrefix() to determine if the filename matches the prefix. You can copy the code below: 

function APPmatchPrefix(Prefix, FileName)
   local Part = FileName:sub(1, #Prefix)
   trace(Part, Prefix)
   return (Part == Prefix)
end

See the screenshot below and add a line to MatchFile() to call and invoke the AppmatchPrefix() function.

Concepts used:

 Now change the matching code so we go through the entire prefix list

Let’s modify the code to go through the entire list of prefixes:

for i = 1, #IdList do
   if APPmatchPrefix(IdList[i], JustFileName) then 
      return true
   end
end
return false -- we didn't match anything

And this is what you should see:

Concepts used:

 Commit your changes, alter the component to run on the new commit and run it!

Commit and Push Changes to Git and go to the component card for Choosing the code to run for your component.

And done! The next steps are how you could further refine the code

 Make the configuration more robust by striping white space from the list ClientList

This means refining the APPidList function.

That would involve looping through the list and removing white space from each ID:

Concepts:

 Customize the logging

See Custom Logging

 Customize the status

See Custom Status

There is no limit to how you can streamline the usage of a custom component - if that helps address a bottleneck, then it is well worth it.  

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