Install npmnode-gyprrebuilderr under the project path!

  node.js, question

Project address:

F:\weibo-nodejs (master) (application-name@0.0.1)
 λ npm install
 bcrypt@0.8.5 install F:\weibo-nodejs\node_modules\bcrypt
 node-gyp rebuild
 F:\weibo-nodejs\node_modules\bcrypt {git}{hg}
 {lamb} if not defined npm_config_node_gyp (node "E:\nodejs\node_modules\npm\bin\node-gyp-bin\\..\..\node_modules\node-gyp\bin\node-gyp.js" rebuild )  else (node "" rebuild )
 gyp ERR!  configure error
 gyp ERR!  stack Error: Can't find Python executable "python", you can set the PYTHON env variable.
 gyp ERR!  stack     at failNoPython (E:\nodejs\node_modules\npm\node_modules\node-gyp\lib\configure.js:401:14)
 gyp ERR!  stack     at E:\nodejs\node_modules\npm\node_modules\node-gyp\lib\configure.js:356:11
 gyp ERR!  stack     at FSReqWrap.oncomplete (fs.js:82:15)
 gyp ERR!  System Windows_NT 6.1.7601
 gyp ERR!  command "E:\\nodejs\\node.exe" "E:\\nodejs\\node_modules\\npm\\node_modules\\node-gyp\\bin\\node-gyp.js" "rebuild"
 gyp ERR!  cwd F:\weibo-nodejs\node_modules\bcrypt
 gyp ERR!  node -v v4.4.5
 gyp ERR!  node-gyp -v v3.3.1
 gyp ERR!  not ok
 npm ERR!  Windows_NT 6.1.7601
 npm ERR!  argv "E:\\nodejs\\node.exe" "E:\\nodejs\\node_modules\\npm\\bin\\npm-cli.js" "install"
 npm ERR!  node v4.4.5
 npm ERR!  npm  v2.15.5
 npm ERR!  code ELIFECYCLE
 npm ERR!  bcrypt@0.8.5 install: `node-gyp rebuild`
 npm ERR!  Exit status 1
 npm ERR!
 npm ERR!  Failed at the bcrypt@0.8.5 install script 'node-gyp rebuild'.
 npm ERR!  This is most likely a problem with the bcrypt package,
 npm ERR!  not with npm itself.
 npm ERR!  Tell the author that this fails on your system:
 npm ERR!  node-gyp rebuild
 npm ERR!  You can get information on how to open an issue for this project with:
 npm ERR!  npm bugs bcrypt
 npm ERR!  Or if that isn't available, you can get their info via:
 npm ERR!
 npm ERR!  npm owner ls bcrypt
 npm ERR!  There is likely additional logging output above.
 npm ERR!  Please include the following file with any support request:
 npm ERR!  F:\weibo-nodejs\npm-debug.log

What is the reason for this?

Error: Can’t find Python executable “python”, you can set the PYTHON env variable.
Python cannot be found. You can install it next, configure environment variables, and restart a console to execute commands.