Troubleshooting Certificate Verification Failure: Understanding SSL and Certificates
When attempting to retrieve data from websites using Python's urllib.request package, you may encounter an error stating "certificate verify failed: unable to get local issuer certificate." This issue arises when your system lacks the necessary SSL certificates to validate the website's authenticity.
How SSL Works
Secure Socket Layer (SSL) is a protocol that encrypts communication between a client and a server. To establish a secure connection, the server presents a signed certificate issued by a trusted authority, known as a Certificate Authority (CA).
Certifi and Install Certificates.command
One solution to resolve the certificate verification failure is to install Python's Certifi package, a collection of trusted CA certificates. Alternatively, you can run the "Install Certificates.command" utility provided in Mac OS High Sierra.
Both methods add trusted CA certificates to your system, allowing your Python script to verify the website's certificate during SSL communication.
Recommendations for Further Learning
To enhance your knowledge of SSL, certificates, and security:
- Mozilla Developer Network (MDN): https://developer.mozilla.org/en-US/docs/Glossary/Certificate_authority
- Transport Layer Security (TLS) Explained: https://blog.cloudflare.com/everything-you-need-to-know-about-tls/
- OpenSSL User Guide: https://www.openssl.org/docs/manmaster/
- Python's SSL Certificate Verification in Requests Library: https://requests.readthedocs.io/en/latest/user/advanced/#ssl-cert-verification
The above is the detailed content of Why is My Python Script Failing to Verify SSL Certificates?. For more information, please follow other related articles on the PHP Chinese website!

Arraysarebetterforelement-wiseoperationsduetofasteraccessandoptimizedimplementations.1)Arrayshavecontiguousmemoryfordirectaccess,enhancingperformance.2)Listsareflexiblebutslowerduetopotentialdynamicresizing.3)Forlargedatasets,arrays,especiallywithlib

Mathematical operations of the entire array in NumPy can be efficiently implemented through vectorized operations. 1) Use simple operators such as addition (arr 2) to perform operations on arrays. 2) NumPy uses the underlying C language library, which improves the computing speed. 3) You can perform complex operations such as multiplication, division, and exponents. 4) Pay attention to broadcast operations to ensure that the array shape is compatible. 5) Using NumPy functions such as np.sum() can significantly improve performance.

In Python, there are two main methods for inserting elements into a list: 1) Using the insert(index, value) method, you can insert elements at the specified index, but inserting at the beginning of a large list is inefficient; 2) Using the append(value) method, add elements at the end of the list, which is highly efficient. For large lists, it is recommended to use append() or consider using deque or NumPy arrays to optimize performance.

TomakeaPythonscriptexecutableonbothUnixandWindows:1)Addashebangline(#!/usr/bin/envpython3)andusechmod xtomakeitexecutableonUnix.2)OnWindows,ensurePythonisinstalledandassociatedwith.pyfiles,oruseabatchfile(run.bat)torunthescript.

When encountering a "commandnotfound" error, the following points should be checked: 1. Confirm that the script exists and the path is correct; 2. Check file permissions and use chmod to add execution permissions if necessary; 3. Make sure the script interpreter is installed and in PATH; 4. Verify that the shebang line at the beginning of the script is correct. Doing so can effectively solve the script operation problem and ensure the coding process is smooth.

Arraysaregenerallymorememory-efficientthanlistsforstoringnumericaldataduetotheirfixed-sizenatureanddirectmemoryaccess.1)Arraysstoreelementsinacontiguousblock,reducingoverheadfrompointersormetadata.2)Lists,oftenimplementedasdynamicarraysorlinkedstruct

ToconvertaPythonlisttoanarray,usethearraymodule:1)Importthearraymodule,2)Createalist,3)Usearray(typecode,list)toconvertit,specifyingthetypecodelike'i'forintegers.Thisconversionoptimizesmemoryusageforhomogeneousdata,enhancingperformanceinnumericalcomp

Python lists can store different types of data. The example list contains integers, strings, floating point numbers, booleans, nested lists, and dictionaries. List flexibility is valuable in data processing and prototyping, but it needs to be used with caution to ensure the readability and maintainability of the code.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Dreamweaver Mac version
Visual web development tools

DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

Dreamweaver CS6
Visual web development tools

SublimeText3 Linux new version
SublimeText3 Linux latest version

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.
