Algorithm to generate a hash value for each file to upload to the server.
<script type="text/javascript" src="iuembed.js"> </script> <script type="text/javascript"> var iu = new ImageUploaderWriter("ImageUploaderID", 610, 500); //...other params... iu.addParam("HashAlgorithm", ""); //...other params... iu.writeHtml(); </script>
getImageUploader("ImageUploaderID").setHashAlgorithm(value);
value = getImageUploader("ImageUploaderID").getHashAlgorithm();A string value which specifies what hash algorithm to use. If an empty string is specified, no hash value is calculated.
Possible values are listed in the table below.
| Hash algorithm name | Description |
|---|---|
| SHA | SHA hash algorithm. |
| MD2 | MD2 hash algorithm. |
| MD5 | MD5 hash algorithm. |
You can specify several hash algorithms separated by semicolon.
Default value is "".
To get hash value on the server side, you should extract POST field which is named in the
following way:
HashCodeXXX_N
, where
XXX
is the string
value specified in this property (algorithm name), and
N
is the index of the file in
the request.
When hash value is added to the request, it is encoded with Base64 algorithm. So it is necessary to decode it back. Most server platforms already have facilities to work Base64 encoding, however if you have problems with it, refer RFC 3548.
The hash is calculated only for the original file, not for the thumbnails (even if the source file is not uploaded).
If you specify several algorithms, several
hash values will be sent (for each algorithm). E.g. if you specify a value
MD5;SHA, you will get the following POST fields:
HashCodeMD5_1, HashCodeMD5_2, etc.
HashCodeSHA_1, HashCodeSHA_2, etc.
Hash calculation is quite resource-intensive operation. That's why if you need not verify uploaded files on the server, it makes sense to disable this feature to make Image Uploader faster. To do it, just specify empty string in this property.