(PowerShell) Download Binary File to In-Memory Bytes

This example demonstrates how to download the binary content of a file from Google Drive directly into local memory.

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

$success = $true

# It requires the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# This example uses a previously obtained access token having permission for the 
# Google Drive scope.

$gAuth = New-Object Chilkat.AuthGoogle
$gAuth.AccessToken = "GOOGLE-DRIVE-ACCESS-TOKEN"

$rest = New-Object Chilkat.Rest

# Connect using TLS.
# A single REST object, once connected, can be used for many Google Drive REST API calls.
# The auto-reconnect indicates that if the already-established HTTPS connection is closed,
# then it will be automatically re-established as needed.
$bAutoReconnect = $true
$success = $rest.Connect("www.googleapis.com",443,$true,$bAutoReconnect)

# Provide the authentication credentials (i.e. the access token)
$rest.SetAuthGoogle($gAuth)

# ------------------------------------------------------------------------------
# To download a file, we must know the file ID.
# In a previous example (see Build Local Metadata Cache
# we built a local cache to make it easy to lookup file IDs given a file path.
# Let's say we want to download "testFolder/abc/123/penguins.jpg".
# First we lookup the fileId in the cache.  With the fileId, we can download the file.
$gdCache = New-Object Chilkat.Cache
$gdCache.Level = 0
$gdCache.AddRoot("C:/ckCache/googleDrive")

$fileId = $gdCache.FetchText("testFolder/abc/123/penguins.jpg")
if ($gdCache.LastMethodSuccess -ne $true) {
    $("Filepath not found in cache.")
    exit
}

# We need to send a GET request like this:
# GET https://www.googleapis.com/drive/v3/files/fileId?alt=media
# The fileId is part of the path.
$sbPath = New-Object Chilkat.StringBuilder
$sbPath.Append("/drive/v3/files/")
$sbPath.Append($fileId)
$rest.AddQueryParam("alt","media")

# To download to memory, we'll send the request in one call, then receive
# the response header, and then the response body.
# If the response header indicates failure or an unexpected response, then the
# body is not the data we desire.

# First send the HTTP request.
$success = $rest.SendReqNoBody("GET",$sbPath.GetAsString())
if ($success -ne $true) {
    $($rest.LastErrorText)
    exit
}

# Get the response header.
$statusCode = $rest.ReadResponseHeader()
if ($statusCode -ne 200) {
    $("response status code = " + $rest.ResponseStatusCode)
    $("response status text = " + $rest.ResponseStatusText)
    $("response header: " + $rest.ResponseHeader)

    # Read the response body (which should be error text or HTML)
    $errResponseBody = $rest.ReadRespBodyString()
    if ($rest.LastMethodSuccess -eq $true) {
        $("response body: " + $errResponseBody)
    }

    exit
}

# Read the response body, which should contain the file data.

$jpgBytes = $rest.ReadRespBodyBinary()
if ($rest.LastMethodSuccess -ne $true) {
    $($rest.LastErrorText)
    exit
}

# Save jpgBytes to a file so we can examine the file to verify that it worked.
$fac = New-Object Chilkat.FileAccess
$fac.WriteEntireFile("qa_output/penguins_out.jpg",$jpgBytes)

$("File downloaded.")