ReadFileContent

Reads the text content of a file that was downloaded using DownloadBlobFiles.

Syntax 

ReadFileContent(handleId)

Parameters

  • handleId (string): The unique handle ID returned by DownloadBlobFiles

Returns

  • string: The text content of the file, or null if the handle is not found or the file cannot be read

Description

Retrieves the content of a downloaded file using its handle ID. Files must first be downloaded using DownloadBlobFiles, which returns handle objects containing the id property needed for this function.

This function reads the entire file as text (UTF-8). For binary files or structured data formats, consider using the specialized read functions (ReadCsv, ReadExcel, ReadJson, ReadXml) with base64-encoded content instead.

Examples

Read a downloaded file 

var connectionString = GetSecret("EXTERNAL_BLOB_CONNECTION")

# Download files from external blob storage
var files = DownloadBlobFiles(connectionString, "data-container", ["config/settings.json"])

if Length(files) > 0 then
    var content = ReadFileContent(files[0].id)

    if content != null then
        Log("Information", "File content length: " + Length(content))
        # Parse as JSON
        var settings = Parse(content)
        Log("Information", "Setting value: " + settings.someProperty)
    else
        Log("Error", "Could not read file content")
    end
else
    Log("Warning", "No files downloaded")
end

Process multiple downloaded files 

var connectionString = GetSecret("DATA_LAKE_CONNECTION")

# Download all CSV files from a folder
var handles = DownloadBlobFiles(connectionString, "reports", "daily/", 50)

Log("Information", "Downloaded " + Length(handles) + " files")

foreach handle in handles do
    var content = ReadFileContent(handle.id)

    if content != null then
        Log("Information", "Processing: " + handle.fileName + " (" + Length(content) + " chars)")

        # For CSV files, you might want to parse the content
        # Note: For proper CSV parsing, use ReadCsv with base64 content
        var lines = Split(content, "\n")
        Log("Debug", "File has " + Length(lines) + " lines")
    else
        Log("Warning", "Could not read: " + handle.fileName)
    end
end

Read and process text file 

var connectionString = GetSecret("IMPORT_STORAGE_CONNECTION")

var files = DownloadBlobFiles(connectionString, "imports", ["batch/emails.txt"])

if Length(files) > 0 then
    var content = ReadFileContent(files[0].id)

    if content != null then
        # Split by newlines to get individual email addresses
        var emails = Split(content, "\n")
        var validCount = 0

        foreach email in emails do
            var trimmed = Trim(email)
            if trimmed != "" and Contains(trimmed, "@") then
                validCount = validCount + 1
                Log("Debug", "Valid email: " + trimmed)
            end
        end

        Log("Information", "Found " + validCount + " valid email addresses")
    end
end

Error handling 

var connectionString = GetSecret("BLOB_CONNECTION")
var files = DownloadBlobFiles(connectionString, "container", ["path/to/file.txt"])

if Length(files) == 0 then
    Log("Error", "File not found or download failed")
    Data._payload = { error: "File not found" }
    Data._statusCode = 404
    return
end

var content = ReadFileContent(files[0].id)

if content == null then
    Log("Error", "Could not read file content - file may be binary")
    Data._payload = { error: "Could not read file" }
    Data._statusCode = 500
    return
end

Data._payload = { content: content, size: Length(content) }

Notes

  • The file must be downloaded first using DownloadBlobFiles
  • Returns null if the handle ID is invalid, expired, or the file cannot be read
  • Reads files as UTF-8 text - binary files may not be read correctly
  • Handle IDs are GUIDs and are case-insensitive
  • Downloaded files are temporary and cleaned up after script execution

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