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import datetime | |
import hashlib | |
import hmac | |
import urllib.parse | |
def aws_sig_v4_headers(access_key_id, secret_access_key, pre_auth_headers, | |
service, region, host, method, path, query, payload): | |
algorithm = 'AWS4-HMAC-SHA256' |
The following list of questions was taken from https://www.reddit.com/r/ethereum/comments/72reba/do_you_have_deep_questions_about_solidity_or_the/
An updated summary on the different ways one could have two contracts interact (DELEGATECALL, STATICCALL, libraries, all that stuff) with clear pros/cons for each (gas cost, whether it requires EVM assembly directives, etc)
Question by /u/drcode
I won't talk about low-level opcodes here because of the brevity of the answer. In general, there are four ways functions can be called in Solidity:
- http://stackoverflow.com/questions/804115 (
rebase
vsmerge
). - https://www.atlassian.com/git/tutorials/merging-vs-rebasing (
rebase
vsmerge
) - https://www.atlassian.com/git/tutorials/undoing-changes/ (
reset
vscheckout
vsrevert
) - http://stackoverflow.com/questions/2221658 (HEAD^ vs HEAD~) (See
git rev-parse
) - http://stackoverflow.com/questions/292357 (
pull
vsfetch
) - http://stackoverflow.com/questions/39651 (
stash
vsbranch
) - http://stackoverflow.com/questions/8358035 (
reset
vscheckout
vsrevert
)
Ethereum tutorials all advise downloading the Mist wallet and beginning dev. The only problem is that the testnet and real blockchain are huge and take hours to download. What follows is a recipe for quickly setting up a small blockchain and pre-mining it with some test ethereum
The following is done in Linux but will work in MacOS and should have equivalent command line options in Windows. Where I don't give detailed instructions, it's because a quick google search will fill in the blanks.
Install geth https://github.com/ethereum/go-ethereum/wiki/geth
install Mist https://github.com/ethereum/mist/releases
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# The initial version | |
if [ ! -f .env ] | |
then | |
export $(cat .env | xargs) | |
fi | |
# My favorite from the comments. Thanks @richarddewit & others! | |
set -a && source .env && set +a |
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# http://webapps.stackexchange.com/questions/39587/view-estimated-size-of-github-repository-before-cloning | |
# tested on macOS | |
echo https://github.com/torvalds/linux.git | perl -ne 'print $1 if m!([^/]+/[^/]+?)(?:\.git)?$!' | xargs -I{} curl -s -k https://api.github.com/repos/'{}' | grep size | |
# output: | |
# "size": 1746294, |
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# After Ubuntu 16.04, Systemd becomes the default. | |
# It is simpler than https://gist.github.com/Doowon/38910829898a6624ce4ed554f082c4dd | |
[Unit] | |
Description=Jupyter Notebook | |
[Service] | |
Type=simple | |
PIDFile=/run/jupyter.pid | |
ExecStart=/home/phil/Enthought/Canopy_64bit/User/bin/jupyter-notebook --config=/home/phil/.jupyter/jupyter_notebook_config.py |
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# Hello, and welcome to makefile basics. | |
# | |
# You will learn why `make` is so great, and why, despite its "weird" syntax, | |
# it is actually a highly expressive, efficient, and powerful way to build | |
# programs. | |
# | |
# Once you're done here, go to | |
# http://www.gnu.org/software/make/manual/make.html | |
# to learn SOOOO much more. |
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