All,
I am trying to determine if I am dealing with an Excel file that I
upload to a Web server.
Here is the first test - to verify the magic number of the file that I
have:
#Check the magic number first to see if it's even an Office file
magic_number = nil
File.open(path_to_file, "r") do |f|
magic_number = f.read(6)
end
return false unless
magic_number.unpack('H*').to_s().eql?('d0cf11e0a1b1')
This seems a little bit less than optimal. I have to unpack my string
into an array and then reconvert it back to a string to compare it?
Surely there is a simpler way?
Should magic_number.eql?('d0cf11e0a1b1') work?
Wes
···
--
Posted via http://www.ruby-forum.com/.
magic_number.eql?('d0cf11e0a1b1') doesn't work which kind of makes
sense.
Anyhow, is this the best way to do it? It feels very hokey to me :).
Thanks for the patience as well - I rarely inspect magic numbers...
WG
Wes Gamble wrote:
···
All,
I am trying to determine if I am dealing with an Excel file that I
upload to a Web server.
Here is the first test - to verify the magic number of the file that I
have:
#Check the magic number first to see if it's even an Office file
magic_number = nil
File.open(path_to_file, "r") do |f|
magic_number = f.read(6)
end
return false unless
magic_number.unpack('H*').to_s().eql?('d0cf11e0a1b1')
This seems a little bit less than optimal. I have to unpack my string
into an array and then reconvert it back to a string to compare it?
Surely there is a simpler way?
Should magic_number.eql?('d0cf11e0a1b1') work?
Wes
--
Posted via http://www.ruby-forum.com/\.
Wes Gamble wrote:
All,
I am trying to determine if I am dealing with an Excel file that I upload to a Web server.
Here is the first test - to verify the magic number of the file that I have:
#Check the magic number first to see if it's even an Office file
magic_number = nil
File.open(path_to_file, "r") do |f|
magic_number = f.read(6)
end
return false unless magic_number.unpack('H*').to_s().eql?('d0cf11e0a1b1')
This seems a little bit less than optimal. I have to unpack my string into an array and then reconvert it back to a string to compare it?
Surely there is a simpler way?
Should magic_number.eql?('d0cf11e0a1b1') work?
Wes
I'm guessing the magic number is constant? Why not construct a constant string that is the magic number and then compare the bytes you get from the file to that string? Simple, fast, and ez-to-read.
MAGIC_STRING = [0xd0,0xcf,0x11,0xe0,0xa1,0xb1].pack('c*').freeze
if magic_number == MAGIC_STRING ...
There are a number of simpler ways, one might be
EXCEL_FILE_MAGIC_NUMBER = ['d0cf11e0a1b1'].pack('H*')
# later
magic_number == EXCEL_FILE_MAGIC_NUMBER # => true or false
or you can use octal or hex escapes to have a string literal to compare against e.g.
irb(main):006:0> "\320\317\021\340\241\261" == "\xd0\xcf\x11\xe0\xa1\xb1"
=> true
Maybe there are good bits of the Pickaxe (Programming Ruby) or some on-line tutorials which can help you see some of the more ruby-ish ways to do things.
Hope this helps,
Mike
···
On 21-Mar-06, at 6:46 PM, Wes Gamble wrote:
All,
I am trying to determine if I am dealing with an Excel file that I
upload to a Web server.
Here is the first test - to verify the magic number of the file that I
have:
#Check the magic number first to see if it's even an Office file
magic_number = nil
File.open(path_to_file, "r") do |f|
magic_number = f.read(6)
end
return false unless
magic_number.unpack('H*').to_s().eql?('d0cf11e0a1b1')
This seems a little bit less than optimal. I have to unpack my string
into an array and then reconvert it back to a string to compare it?
Surely there is a simpler way?
Should magic_number.eql?('d0cf11e0a1b1') work?
--
Mike Stok <mike@stok.ca>
http://www.stok.ca/~mike/
The "`Stok' disclaimers" apply.
An even better way would be to take advantage of the fact that I'm
uploading through a browser and just look at the MIME type
Man, I'm dumb :).
But on the other hand, now I now about the IO module, and modules in
general and all kinds of things.
Thanks, everybody.
Wes
Mike Stok wrote:
···
On 21-Mar-06, at 6:46 PM, Wes Gamble wrote:
magic_number = nil
Should magic_number.eql?('d0cf11e0a1b1') work?
There are a number of simpler ways, one might be
EXCEL_FILE_MAGIC_NUMBER = ['d0cf11e0a1b1'].pack('H*')
# later
magic_number == EXCEL_FILE_MAGIC_NUMBER # => true or false
or you can use octal or hex escapes to have a string literal to
compare against e.g.
irb(main):006:0> "\320\317\021\340\241\261" == "\xd0\xcf\x11\xe0\xa1
\xb1"
=> true
Maybe there are good bits of the Pickaxe (Programming Ruby) or some
on-line tutorials which can help you see some of the more ruby-ish
ways to do things.
Hope this helps,
Mike
--
Mike Stok <mike@stok.ca>
Mike Stok
The "`Stok' disclaimers" apply.
--
Posted via http://www.ruby-forum.com/\.