CODEWITHSUNDEEP
imagelivecode
Tate83
Tate83

Reputation: 274

Check if file is an image

I build a way to add an image to card from a file and store it in a custom property. This works fine. 

 answer file tImageDialogTranslations with type "Images|jpg|jpeg|png"
 if  it is not empty then
  put  it into tMyImagePath

  put url("binfile:" & tMyImagePath) into tMyImage
  put base64encode( tMyImage) into tBase64ImgData

  # store image in cust prop
  set the cImageBlob of img "img_collection_picture" to  tBase64ImgData 

  #show image
  put base64decode(tBase64ImgData) into tShowImage
  set the text of image "img_collection_picture" to tShowImage
 end if

Sadly, when I add an * in the file answer dialog I can also choose another file type like txt which then is stored in the custom property but not displayed in the image.

How can I check if the user really chose a valid image file?

Upvotes: 0

Views: 261

Answers (2)

Tate83
Tate83

Reputation: 274

I figured it out and thought I'd share the whole relevant part:

answer file tImageDialogTranslations with type "Images|jpg,jpeg,png,gif"
if it is not empty then
  put  it into tMyImagePath
  put url("binfile:" & tMyImagePath) into tMyImage
  put binarydecode("H8",tMyImage,tMyImageHex) -- to check if it is actually an image
  put base64encode( tMyImage) into tBase64ImgData


  set the itemdel to comma
    if tMyImageHex is among the items of "ffd8ffe0,47494638,89504e47"  then

     ### store image in custom property
     set the cImageBlob of img "img_collection_picture" to  tBase64ImgData 

     ### now display image in field
     put base64decode(tBase64ImgData) into tShowImage
     set the text of image "img_collection_picture" to tShowImage

    else
     # do nothing / error 100499
     answer "Error 100499: Please choose an image file. "
    end if

 else
     # do nothing since no file was chosen
 end if

Upvotes: 0

Manmay
Manmay

Reputation: 844

I think you can validate by checking the file extension or file's magic number. Those info can assist you to ensure that the file is an image file or not. Scanning the file content to validate if it is an image file is not a good idea.

Upvotes: 3

Related Questions