I have a small bash script that download files from another server, sometimes download gets interrupted. How can I check if wget has completed download successfully?
if it gets interrupted then it may have part of the file ?
If it has part of the file - how would you know if the file is the full file or not depends on two different checks.
Either you have the actual file maybe from another attempt of the same script executed then the files compared - you could compare the files using md5 to ensure their identical.
The other less accurate method could be done over 1 attempt and you could do a du -sk on the file and if its above a certain size it passes - this by no way can ensure if file is 100% there if cut off 99%
but you could also look into wget -c which resumes downloads ---
so maybe run it twice with this option:
wget --help 2>&1 |grep "\-\-continue"
-c, --continue resume getting a partially-downloaded file.
if it is a web server you are in control of you could install:
https://metacpan.org/pod/Apache::OpenIndex
I think this displays the md5 sum of the directoryindex so you can then parse this and compare to local md5 sum of your downloaded file - if a miss match run wget -c
Related
I have an wget command running, but due to the website it regularly downloads "fake data". So, I am now downloading it dozens of times to get the correct content.
I now want the following:
use the wget command
check if in that directory are files <100kB
if yes ->use robocopy to save the >100kB files to another folder; repeat with wget
if no -> stop
I have the wget command and the robocopy command.
I only need now the function to check if an directory has a file <100kB and how to put this together into an cmd/powershell/bat or whatever.
How would the command for that look like? I have especially no idea how to check the files.
I have this wget command:
sudo wget --user-agent='some-agent' --referer=http://some-referrer.html -N -r -nH --cut-dirs=x --timeout=xxx --directory-prefix=/directory/for/downloaded/files -i list-of-files-to-download.txt
-N will check if there is actually a newer file to download.
-r will turn the recursive retrieving on.
-nH will disable the generation of host-prefixed directories.
--cut-dirs=X will avoid the generation of the host's subdirectories.
--timeout=xxx will, well, timeout :)
--directory-prefix will store files in the desired directorty.
This works nice, no problem.
Now, to the issue:
Let's say my files-to-download.txt has these kind of files:
http://website/directory1/picture-same-name.jpg
http://website/directory2/picture-same-name.jpg
http://website/directory3/picture-same-name.jpg
etc...
You can see the problem: on the second download, wget will see we already have a picture-same-name.jpg, so it won't download the second or any of the following ones with the same name. I cannot mirror the directory structure because I need all the downloaded files to be in the same directory. I can't use the -O option because it clashes with --N, and I need that. I've tried to use -nd, but doesn't seem to work for me.
So, ideally, I need to be able to:
a.- wget from a list of url's the way I do now, keeping my parameters.
b.- get all files at the same directory and being able to rename each file.
Does anybody have any solution to this?
Thanks in advance.
I would suggest 2 approaches -
Use the "-nc" or the "--no-clobber" option. From the man page -
-nc
--no-clobber
If a file is downloaded more than once in the same directory, >Wget's behavior depends on a few options, including -nc. In certain >cases, the local file will be
clobbered, or overwritten, upon repeated download. In other >cases it will be preserved.
When running Wget without -N, -nc, -r, or -p, downloading the >same file in the same directory will result in the original copy of file >being preserved and the second copy
being named file.1. If that file is downloaded yet again, the >third copy will be named file.2, and so on. (This is also the behavior >with -nd, even if -r or -p are in
effect.) When -nc is specified, this behavior is suppressed, >and Wget will refuse to download newer copies of file. Therefore, ""no->clobber"" is actually a misnomer in
this mode---it's not clobbering that's prevented (as the >numeric suffixes were already preventing clobbering), but rather the >multiple version saving that's prevented.
When running Wget with -r or -p, but without -N, -nd, or -nc, >re-downloading a file will result in the new copy simply overwriting the >old. Adding -nc will prevent this
behavior, instead causing the original version to be preserved >and any newer copies on the server to be ignored.
When running Wget with -N, with or without -r or -p, the >decision as to whether or not to download a newer copy of a file depends >on the local and remote timestamp and
size of the file. -nc may not be specified at the same time as >-N.
A combination with -O/--output-document is only accepted if the >given output file does not exist.
Note that when -nc is specified, files with the suffixes .html >or .htm will be loaded from the local disk and parsed as if they had been >retrieved from the Web.
As you can see from this man page entry, the behavior might be unpredictable/unexpected. You will need to see if it works for you.
Another approach would be to use a bash script. I am most comfortable using bash on *nix, so forgive the platform dependency. However the logic is sound, and with a bit of modifications, you can get it to work on other platforms/scripts as well.
Sample pseudocode bash script -
for i in `cat list-of-files-to-download.txt`;
do
wget <all your flags except the -i flag> $i -O /path/to/custom/directory/filename ;
done ;
You can modify the script to download each file to a temporary file, parse $i to get the filename from the URL, check if the file exists on the disk, and then take a decision to rename the temp file to the name that you want.
This offers much more control over your downloads.
I want to download web using wget, but to make it more like a real user I would like to make small random delays between requests.
I'm executing wget via cmd.
You can add the below code into your command line which adds a ten second wait in between server requests.
-w 10
And you can also include
--random-wait
Into your command line with -w option which will vary the wait by 0.5 and 1.5 times the value you provide here.
Perfect, adding "-w 3" on the front end of a recursive download prevented the server from becoming overloaded.
as in
wget -w 3 -m -np -c -R "index.html*" "http://example.com.whatever/public/files/"
wait 3
mirroring to recurse all folder depths, and use source timestamps
no parent upward traversal
continue partially downloads
reject any files named index.html
target host URL with the desired recursive files and folders
hope this helps someone else
I'm downloading some .mp3 files (all legal) via wget :
wget -r -nc files.myserver.com
I have to stop the download sometimes and at that times the file is partially downloaded. For example a 10 minutes record.mp3 file become 4 minutes record.mp3 file. It's playing correctly but incomplete.
If I use the same command above, because the record.mp3 file is already exist in my local computer wget skips that file although it isn't complete.
I wonder if there is a way to check the file sizes and if the file size in the remote server and local computer isn't same re-download it. (I've learned the --spider command gives the file size but is there any other command that automatically check the file sizes and download or not).
I would go with wget's -N option for timestamping, but note that wget will only compare the file sizes if you also specify the --no-if-modified-since option. Without it, incomplete files are indeed skipped on the next run because they receive a timestamp of the current time, which is newer than that on the server.
The reason is probably that with only -N, a GET request is sent for the file with the If-Modified-Since field set. The server responds with either 200 or 304, but the 304 doesn't contain the file size so wget can't check it.
With --no-if-modified-since wget sends a HEAD request instead to get the timestamp and file size, and checks both.
What I use for recursive download of a folder:
wget -T 300 -nv -t 1 -r -nd -np -l 1 -N --no-if-modified-since -P $my_folder $my_url
With:
-T 300: Set the network timeout to 300 seconds
-nv: Turn off verbose without being completely quiet
-t 1: Set number of tries to 1
-r: Turn on recursive retrieving
-nd: Do not create a hierarchy of directories when retrieving recursively
-np: Do not ever ascend to the parent directory when retrieving recursively
-l 1: Specify recursion maximum depth 1
-N: Turn on time-stamping
--no-if-modified-since: Do not send If-Modified-Since header in ‘-N’ mode, send preliminary HEAD request instead
You may try the -c option to continue the download of partially downloaded files, however the manual gives an explicit warning:
You need to be especially careful of this when using -c in conjunction
with -r, since every file will be considered as an "incomplete
download" candidate.
While there is no perfect solution to this problem you could try to use -N option to turn on timestamping. This might prevent errors when the file has changed on the server but only if the server supports timestamping and partial downloads. Try it and see how it goes.
wget -r -N -c files.myserver.com
If you need check if file was partially downloaded (has different size) or updated on remote server by timestamp and must be in this case updated locally you need use -N option.
Here some additional info about -N (--timestamping) option from Wget docs:
If the local file does not exist, or the sizes of the files do not match, Wget will download the remote file no matter what the
time-stamps say.
Added From: https://www.gnu.org/software/wget/manual/wget.html (Chapter: 5 Time-Stamping)
I'm using wget in a cron job to fetch a .jpg file into a web server folder once per minute (with same filename each time, overwriting). This folder is "live" in that the web server also serves that image from there. However if someone web-browses to that page during the time the image is being fetched, it is considered a jpg with errors and says so in the browser. So what I need to do is, similar to when Firefox is downloading a file, wget should write to a temporary file, either in /var or in the destination folder but with a temporary name, until it has the whole thing, then rename in an atomic (or at least negligible-duration) step.
I've read the wget man page and there doesn't seem to be a command line option for this. Have I missed it? Or do I need to do two commands in my cron job, a wget and a move?
There is no way to do this purely with GNU Wget.
wget's job is to download files and it does that. A simple one line script can achieve what you're looking for:
$ wget -O myfile.jpg.tmp example.com/myfile.jpg && mv myfile.jpg{.tmp,}
Since mv is atomic, atleast on Linux, you get the atomic update of a ready file.
Just wanted to share my solution:
alias wget='func(){ (wget --tries=0 --retry-connrefused --timeout=30 -O download_pkg.tmp "$1" && mv download_pkg.tmp "${1##*/}") || rm download_pkg.tmp; unset -f func; }; func
it creates a function that receives a parameter "url" to download the file to a temporary name. If it is successful, it is renamed to the correct filename extracted from parameter $1 with ${1##*/}. and if it fails, deletes the temp file. If the operation is aborted, the temp file will be replace on the next run. after all, unset -f removes the function definition as the alias is executed.