Google Script base64 decode and save file to Drive - google-apps-script

Question

I'm receiving a base64encoded image in a Google Sheets script. I can successfully generate an image by logging
e.postData.contents
then using https://www.base64decode.org/ to decode and generate a .jpg file. But when I try to do the decoding inside the google script and write a jpg file to drive, it is corrupted. It looks similar, but there are some replacement characters inserted. Here's my code:
function doPost(e) {
var decoded = Utilities.base64Decode(e.postData.contents, Utilities.Charset.UTF_8);
var blob = Utilities.newBlob(decoded);
DriveApp.createFile('img_'+date+'.jpg', blob.getDataAsString('Windows-1252'), MimeType.JPEG);
}
I also tried blob.getAs('image/jpeg'), but that just returns a 4-byte file containing the text Blob.
Any ideas? I've tried a few different charsets, and Windows-1252 seems to give the closest results.

Answer 1

How about this sample script? When you use this, please define date. In my test, also I could confirm that the base64 encoded jpeg file could be decoded at https://www.base64decode.org/.
And when you updated doPost(), please be careful as follows. Please redeploy your script to Web Apps as a new version. If this is not carried out, script of the deployed Web Apps is not updated.
Sample script :
function doPost(e) {
var decoded = Utilities.base64Decode(e.parameters.contents, Utilities.Charset.UTF_8);
var blob = Utilities.newBlob(decoded, "image/jpeg", 'img_'+date+'.jpg'); // Please define date.
DriveApp.createFile(blob);
}
Curl sample :
If you want to try your doPost() using curl, you can use following command. When you use this, please input filename which is base64 encoded file and Web Apps URL.
curl -L -F "contents=`cat ### Filename ###`" "https://script.google.com/macros/s/#####/exec"
If I misunderstand your question, I'm sorry.

Answer 2

I am facing the same issue. my spreadsheet is showing an image but broken and unsupported. see the screenshot columns
I am sending the base64 image from autohotkey script. here is my autohotkey snippet:
Base64Enc(File="") { ; By SKAN / 18-Aug-2017 https://www.autohotkey.com/boards/viewtopic.php?t=35964
Local Rqd := 0, B64, B := "", N := 0 - LineLength + 1 ; CRYPT_STRING_BASE64 := 0x1
FileGetSize,nBytes,%File%
FileRead,Bin,*c %File%
DllCall( "Crypt32.dll\CryptBinaryToString", "Ptr",&Bin ,"UInt",nBytes, "UInt",0x1, "Ptr",0, "UIntP",Rqd )
VarSetCapacity( B64, Rqd * ( A_Isunicode ? 2 : 1 ), 0 )
DllCall( "Crypt32.dll\CryptBinaryToString", "Ptr",&Bin, "UInt",nBytes, "UInt",0x1, "Str",B64, "UIntP",Rqd )
B64:=StrReplace(B64,"`r`n")
return RTrim(B64,"`n")}
; Convert the screenshot to base64 encoded text
screenshotBase64 := Base64Enc(screenshotFile)
; Send the input, file attachment, and screenshot to the Google App Script
WinHttp := ComObjCreate("WinHttp.WinHttpRequest.5.1")
WinHttp.Open("POST", "https://script.google.com/macros/s/AKfycbypXKVB6DQi0xdWNjR1KM3q3A5w1flSedSkqHH3GpvlDCAirn9e_BOgUwhLbuf1LSEHZg/exec")
WinHttp.SetRequestHeader("Content-Type", "application/x-www-form-urlencoded")
fileSize := StrLen("input=" . input . "&screenshot=" . screenshotBase64 . "&file=" . fileBase64 . "&filename=" . fileName)
;WinHttp.SetRequestHeader("Content-Length", fileSize)
WinHttp.Send("input=" . input . "&screenshot=" . screenshotBase64 . "&file=" . fileBase64 . "&filename=" . fileName)
; Get the response from the script and display it
response := WinHttp.ResponseText
msgbox % response
and this is my google app script code:
// Check if a screenshot was sent
if (screenshot) {
// Decode the base64 data
var decodedImage = Utilities.base64Decode(screenshot, Utilities.Charset.UTF_8) || null;
// Check if the decoded data is not null
if (decodedImage) {
// Create a timestamp for the filename
var timestamp = new Date().getTime();
// Create an image from the decoded data
var img = Utilities.newBlob(decodedImage, "image/jpeg", 'screenshot-'+timestamp+'.jpg');
// Get the folder where you want to upload the image
var folder = DriveApp.getFolderById("1Xmkr8vXTsTIQPMUr2UR1TpzJ2YtTHwOu");
// Upload the image to the folder and get the file object
var driveFile = folder.createFile(img,img.getDataAsString('Windows-1252'),);
// Make the file publicly accessible
driveFile.setSharing(DriveApp.Access.ANYONE, DriveApp.Permission.VIEW);
// Get the download URL of the file
imgUrl = "https://drive.google.com/uc?id="+driveFile.getId();
} else {
throw new Error("Error decoding base64 data.");
}
}