When installing ROS, use sudo rosdep init and the error message ERROR: cannot download default sources list from:

Author: Hangzhou Dianzi University-School of Automation-Intelligent Systems and Robot Research Center-Jolen Xie

Q: When installing ROS, an error occurs when using rosdep init.

sudo apt install python-rosdep
sudo rosdep init
rosdep update

Error reported:ERROR: cannot download default sources list from: https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/sources.list.d/20-default.list Website may be down.

A: Solution

1. Download the rosdistro package, github download address , go to my code cloud, download faster download address , unzip and put it in /home/你用户名/the path

2. Modify the files in rosdistrothis package , that is, modify all the URL addresses pointed to in this file to addresses pointing to local files, which is the address of the downloaded package: The following is an example I modified:rosdep/source.list.d/20-default.listrosdistro/rosdep/source.list.d20-default.listraw.githubusercontent.com

   # os-specific listings first
   yaml file:///home/xxx/rosdistro/rosdep/osx-homebrew.yaml osx
   
   # generic
   yaml file:///home/xxx/rosdistro/rosdep/base.yaml
   yaml file:///home/xxx/rosdistro/rosdep/python.yaml
   yaml file:///home/xxx/rosdistro/rosdep/ruby.yaml
   gbpdistro file:///home/xxx/rosdistro/releases/fuerte.yaml fuerte
   # newer distributions (Groovy, Hydro, ...) must not be listed anymore, they are being fetched from the rosdistro index.yaml instead
   
   

   where xxx is your username

3. Modify the following in /usr/lib/python2.7/dist-packages/rosdep2the foldersources_list.pyDEFAULT_SOURCES_LIST_URL

   sudo gedit /usr/lib/python2.7/dist-packages/rosdep2/sources_list.py
   

   Modify DEFAULT_SOURCES_LIST_URL path:

   DEFAULT_SOURCES_LIST_URL = 'file:///home/xxx/rosdistro/rosdep/sources.list.d/20-default.list'

4. Modify the code in the two folders:
   modify file 1

   sudo gedit /usr/lib/python2.7/dist-packages/rosdep2/rep3.py
   

   Modify URL:
   REP3_TARGETS_URL = 'file:///home/xxx/rosdistro/releases/targets.yaml'

   Modify file 2:

   sudo gedit /usr/lib/python2.7/dist-packages/rosdistro/__init__.py
   

   Modify URL:
   DEFAULT_INDEX_URL = 'file:///home/xxx/rosdistro/index-v4.yaml'

5. Initialize again rosdep. During this period, you may be reminded 20-default.listthat it has been downloaded. Just delete it and then rosdepit will be fine.

   sudo rosdep init
   rosdep update
   

You can roscoretest whether the installation is successful