Screenshot of error message is as follows 
error content:
[ComposerDownloaderTransportException]
The "https://packagist.org/p/provider-2018-01%245364abf20a2335046831825d0f875bd8117c10523d85a475acb2056d7214e62e.
json" file could not be downloaded (HTTP/1.1 404 Not Found)
the image has been changed to a domestic one
solved. I don't know why setting the image on the command line is invalid, so I manually set the image
image in composer and do not change it to domestic image. If your image is domestic, you will not visit the website https://packagist.org. This website is foreign. And it's slow. Please refer to the setting of composer Chinese image carefully. Don't finish it by typing an order. And the address you gave, the visit to foreign websites is indeed 404. This file is gone
thinkphp5 composer tp5 composer ...
it s embarrassing. I have tried N times, my system is win10 environment is phpstudy integrated environment! in my php.ini, openssl has been opened and CA certificate has been downloaded. ...
what does the ^ in "^ 3.4 " below stand for? "symfony http-foundation ": "^ 3.4 " ...
problem description according to the instructions on the official website, you cannot pull a package when you submit a package to composer, but pull it to composer require. package address is: https: packagist.org package. I have tried to type tag...
for example, what if you continue to rely on packA in composer require packA, packA? cannot be infinitely recursive, so how does it deal with it? think about it casually, and if you have a boss who knows, you will have trouble to solve the problem....