# How to know if completely donwloaded

**URL:** <https://www.ruby-forum.com/t/how-to-know-if-completely-donwloaded/165438>\
**Category:** Ruby\
**Created:** [April 14, 2009, 12:33am UTC](https://www.ruby-forum.com/t/how-to-know-if-completely-donwloaded/165438 "2009-04-14T00:33:16Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![dymyker46](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ce7236/32.png) [@dymyker46](https://www.ruby-forum.com/u/dymyker46)\
**Post date:** [April 14, 2009, 12:33am UTC](https://www.ruby-forum.com/t/how-to-know-if-completely-donwloaded/165438/1 "2009-04-14T00:33:16Z")

</div>

i have tried combining all what i research…

#code starts here:

listofFile = […] #\<-- internet files like PDF, etc…

listofFile.each do |each\_file|  
fileBaseName = File.basename(each\_file)  
filePath = Dir.pwd + ‘/’ + fileBaseName  
begin  
if File.exist?(fileBaseName) != true  
openFileRead = open(each\_file)  
else  
puts “message: File already exist = #{fileBaseName}”  
end  
rescue  
retry  
else  
begin  
writeOut = open(filePath, ‘wb+’)  
#\<-- if internet cuts here, how do i know if its completely downloaded  
writeOut.write(openFileRead.read)  
rescue =\> err  
puts err.message  
puts “error: #{each\_file} – download error.”  
else  
writeOut.close  
end  
end  
end

# code ends here

actually i have internet connection problem here… if the cuts the file  
will be corrupted…

please advice me… or do i miss something…

thanks

---

<div class="post-metadata">

**Author:** ![dymyker46](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ce7236/32.png) [@dymyker46](https://www.ruby-forum.com/u/dymyker46)\
**Post date:** [April 14, 2009, 2:21am UTC](https://www.ruby-forum.com/t/how-to-know-if-completely-donwloaded/165438/2 "2009-04-14T02:21:46Z")

</div>

guy please help me… i cant detect if internet connection cuts the file  
will be corrupted…

---

<div class="post-metadata">

**Author:** ![dymyker46](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ce7236/32.png) [@dymyker46](https://www.ruby-forum.com/u/dymyker46)\
**Post date:** [April 14, 2009, 5:01pm UTC](https://www.ruby-forum.com/t/how-to-know-if-completely-donwloaded/165438/3 "2009-04-14T17:01:16Z")

</div>

Dy Dymy wrote:

> guy please help me… i cant detect if internet connection cuts the file  
> will be corrupted…

It appears that you have already downloaded the files and are attempting  
to validate them after the download process is complete.

I’d suggest a couple of different strategies: one would be to have the  
download process raise an error if the download does not complete and  
the other would be to check the files against the server you are  
downloading from. If possible use an md5 checksum and otherwise you  
could check the size.

If you were downloading zip, gzip files or some other compressed format  
they will usually have built in checksumming, so you could verify the  
file that way. Other file formats might have ways of being validated  
too.

Luke

---

<div class="post-metadata">

**Author:** ![dymyker46](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ce7236/32.png) [@dymyker46](https://www.ruby-forum.com/u/dymyker46)\
**Post date:** [April 16, 2009, 1:49am UTC](https://www.ruby-forum.com/t/how-to-know-if-completely-donwloaded/165438/4 "2009-04-16T01:49:11Z")

</div>

Luke C. wrote:

> Dy Dymy wrote:
> 
> > guy please help me… i cant detect if internet connection cuts the file  
> > will be corrupted…
> 
> It appears that you have already downloaded the files and are attempting  
> to validate them after the download process is complete.
> 
> I’d suggest a couple of different strategies: one would be to have the  
> download process raise an error if the download does not complete and  
> the other would be to check the files against the server you are  
> downloading from. If possible use an md5 checksum and otherwise you  
> could check the size.
> 
> If you were downloading zip, gzip files or some other compressed format  
> they will usually have built in checksumming, so you could verify the  
> file that way. Other file formats might have ways of being validated  
> too.
> 
> Luke

hi Luke,

thanks for the reply…

firstly its correct that i am validating files after i download the  
file.

“raise an error if the download does not complete”  
question: Where i will put my raise error in my code?.. i put a "begin

- rescue - else - end" in my code… hardest part is “.read” has no  
error exemption to check if it reads all throughout the file.

“check the files against the server you are downloading from.”  
question: how do i check the files against the server?

“md5 checksum”  
question: what is md5 checksum?

“check the size”  
comment: after i made this thread, i added my code to check the size.  
Before i download the file i check the size using “uri meta .length” and  
compare it after i download it using “File.size”… but still no use  
because if it break at “.read” the size that i will get is still same as  
what i downloaded… meaning uri.length = File.size

thank ahead…

---

<div class="post-metadata">

**Author:** ![dymyker46](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/ce7236/32.png) [@dymyker46](https://www.ruby-forum.com/u/dymyker46)\
**Post date:** [April 16, 2009, 4:58pm UTC](https://www.ruby-forum.com/t/how-to-know-if-completely-donwloaded/165438/5 "2009-04-16T16:58:05Z")

</div>

> “raise an error if the download does not complete”  
> question: Where i will put my raise error in my code?.. i put a "begin
> 
> - rescue - else - end" in my code… hardest part is “.read” has no  
> error exemption to check if it reads all throughout the file.

I’m talking about adding an exception into the code that does the  
downloading, not the code that reads off the disk. If you can detect  
that a download has ended unexpectedly, you can queue the download to  
start again.

> “check the files against the server you are downloading from.”  
> question: how do i check the files against the server?

By md5 checksum or the file size.

> “md5 checksum”  
> question: what is md5 checksum?

Do some googling my friend.

> “check the size”  
> comment: after i made this thread, i added my code to check the size.  
> Before i download the file i check the size using “uri meta .length” and  
> compare it after i download it using “File.size”… but still no use  
> because if it break at “.read” the size that i will get is still same as  
> what i downloaded… meaning uri.length = File.size

If you know the length the content is supposed to be doing something  
like this:

Net::HTTP.start(“[www.example.com](http://www.example.com)”, 80) {|res| h = res.head(“/”); puts  
h.to\_yaml }

You can check that against the size of the downloaded file.

I think I might be able to help you more if you posted your download  
code.

> thank ahead…

No problem.

Luke