Comments (6)
I got it working. It's a little slow as it requires two while
loops. I'm going to work on making this even faster but for now it's an example. Usage is script url > file
.
Example script:
#!/usr/bin/env bash
#
# Download a file in pure bash.
download() {
IFS=/ read -r _ _ host query <<< "$1"
# Send the HTTP request.
exec 3<"/dev/tcp/${host}/80"; {
printf '%s\r\n%s\r\n\r\n' \
"GET /${query} HTTP/1.0" \
"Host: $host"
} >&3
# Strip the HTTP headers.
while IFS= read -r line; do
[[ "$line" == $'\r' ]] && break
done <&3
# Output the file.
nul='\0'
while IFS= read -d '' -r line || { nul=""; [[ -n "$line" ]]; }; do
printf "%s%b" "$line" "$nul"
done <&3
exec 3>&-
}
download "$1"
from pure-bash-bible.
The fist loop is reasonably slow as it will just drop a sane amount of headers, i can't understand how the 2nd loop (a simple cat !!) can be so complicated (hence, slow i guess)
from pure-bash-bible.
Bash is slow at file IO and it doesn't handle binary data very well. I'm sure it can be optimized but I have some doubts as to whether or not this will ever be faster than wget
/curl
.
from pure-bash-bible.
According to the "bash bible" - yours :p a simple cat alternative might be
file_data="$(<"file")"
Yet i cannot make this work with my design, but i do not understand why
from pure-bash-bible.
cat
handles binary data correctly iirc, bash
doesn't. What causes a larger problem is that bash
handles binary data and null bytes differently depending on which version you're using (In 4.4+ null bytes are skipped and never reach the variable).
from pure-bash-bible.
All the other examples here make sense and can often be faster than invoking another program. However, in the case of networking, I think it makes sense to depend on the binaries, both for useability and performance.
In the case of wget / curl replacements, all of these only work when you have a HTTP endpoint. This code is not going to work for HTTPS.
from pure-bash-bible.
Related Issues (20)
- Alternative to dos2unix
- Inaccurate Caveat for `split()`
- Much More Compatible `reverse_array()`
- Splitting a string on a delimiter HOT 1
- Bash HOT 1
- Pedantic use of ':' "in place of a temporary variable." HOT 1
- shift at least... HOT 2
- basename with one argument fails with set -u HOT 1
- read, store, write a file including nulls
- Is this project active? HOT 4
- Typo in function date HOT 1
- Using coproc with read in non-interactive shells for sleep alternative
- Bash
- [[ ' aaaa' =~ a* ]] && echo ${BASH_REMATCH[0]} || echo no HOT 8
- for loop HOT 3
- wierd if statement HOT 1
- Is the Repository Dead? HOT 1
- Bash HOT 1
- bash read multi-line string with Process Substitution HOT 1
- UPPER CASE %02X instead of x
Recommend Projects
-
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
-
Vue.js
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
-
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
-
TensorFlow
An Open Source Machine Learning Framework for Everyone
-
Django
The Web framework for perfectionists with deadlines.
-
Laravel
A PHP framework for web artisans
-
D3
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
-
Recommend Topics
-
javascript
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
-
web
Some thing interesting about web. New door for the world.
-
server
A server is a program made to process requests and deliver data to clients.
-
Machine learning
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
-
Visualization
Some thing interesting about visualization, use data art
-
Game
Some thing interesting about game, make everyone happy.
Recommend Org
-
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
-
Microsoft
Open source projects and samples from Microsoft.
-
Google
Google ❤️ Open Source for everyone.
-
Alibaba
Alibaba Open Source for everyone
-
D3
Data-Driven Documents codes.
-
Tencent
China tencent open source team.
from pure-bash-bible.