How to upload assets without user interaction?

Question

Context: we sell some magazines and other newspapers on our site, and updating all the cover images manually is a hassle.

I would like the ability to write a url in a field (www.myimageprovider.com/product1) and set a cron job to fetch any new images for the day, for that specific product, and update the entry with the new image.

I'm having a hard time figuring out how to "fake" a file upload from a craft controller/service, as if it was uploaded from the CP form. I have tried something like this:

$file = array();
$url = $entry->getFieldValue('imagefetchurl'); // somegoogleimageurl.com/image.png
$tmpfname = tempnam("/tmp", "UL_IMAGE");
$img = file_get_contents($url);
file_put_contents($tmpfname, $img);
$file['size'] = filesize($tmpfname); // 245 kB
$file['name'] = basename($url); // image.png
$file['tmp_name'] = $tmpfname; // C:\\Windows\\Temp\\UL_XXXX.tmp

$_FILES['assets-upload'] = $file;
$assetOperationResponseModel = craft()->assets->uploadFile(1);

This throws an error

PHP notice

getimagesize(): Read error! - in ...craft\app\services\ImagesService.php(114)

I can see that the image get downloaded, the size and name is correct.

Any pointers and ideas are greatly appreciated

EDIT

After some digging, looks like i have to write my own upload handler for this task. http://www.1-script.com/forums/php/simulate-file-upload-so-that-move-uploaded-file-succeeds-124012-.htm

Basically not possible unless you change the PHP source

I suppose i could override the function, but my instinct tells me that's a bad idea. I will have to go with an alternative approach

Answer 1

Answering my own question for reference.

I was tunneling too hard on the PHP, a simple bash script takes care of the upload.

# assuming the image is already downloaded and no CP-login required
curl -F assets-upload=@/path/to/image mycraftsite/admin/actions/assets/uploadFile

EDIT

Better answer: Thanks to this answer I discovered the insertFileByLocalPath() function in AssetsService.

  $entry = craft()->entries->getEntryById($id);
  if($entry && isset($entry["imageFetchUrl"])) {
    $url = $entry->getFieldValue("imageFetchUrl");
    $tmpfname = tempnam("/tmp", "UL_IMAGE");
    $img = file_get_contents($url);
    file_put_contents($tmpfname, $img);
    craft()->assets->insertFileByLocalPath($tmpfname, 'fetchedImg.jpg', $myFolderId);
  }