如何用Python的subprocess.Popen执行指定wget查询命令？

Hey there! Let's get that wget query running smoothly with subprocess.Popen. There are two primary approaches, each with its own pros—here's how to implement both:

Recommended: Shell=False (Safer, No Injection Risk) #

This is the best practice because it avoids shell parsing, eliminating security risks if your command ever includes untrusted input. You'll split the command into a list of individual arguments:

import subprocess

# Break the command into a list of components
wget_command = [
    "wget",
    "https://www.uniprot.org/uniprot/?query=CDK10+AND+organism:9606+AND+gene_exact:cdk10&columns=id&format=tab"
]

# Execute the command, capturing stdout/stderr as text
process = subprocess.Popen(
    wget_command,
    stdout=subprocess.PIPE,
    stderr=subprocess.PIPE,
    text=True
)

# Retrieve output and wait for the process to finish
stdout, stderr = process.communicate()

# Check if the command succeeded
if process.returncode == 0:
    print("Command ran successfully!")
    print("Output:\n", stdout)
else:
    print("Oops, an error occurred:")
    print(stderr)

If you want wget to save results directly to a specific file (instead of printing to stdout), add the -O flag and your filename to the command list:

wget_command = [
    "wget",
    "-O", "cdk10_results.txt",
    "https://www.uniprot.org/uniprot/?query=CDK10+AND+organism:9606+AND+gene_exact:cdk10&columns=id&format=tab"
]

Alternative: Shell=True (Simpler, But Less Secure) #

If you're working with a trusted command and don't want to split arguments, you can pass the full command as a string with shell=True. Just be aware this is risky if your command includes user-provided input:

import subprocess

# Full command as a single string
wget_command = 'wget "https://www.uniprot.org/uniprot/?query=CDK10+AND+organism:9606+AND+gene_exact:cdk10&columns=id&format=tab"'

process = subprocess.Popen(
    wget_command,
    shell=True,
    stdout=subprocess.PIPE,
    stderr=subprocess.PIPE,
    text=True
)

stdout, stderr = process.communicate()

if process.returncode == 0:
    print("Success!")
else:
    print("Error message:", stderr)

Key Notes: #

• Use text=True (or universal_newlines=True in older Python versions) to get output as strings instead of bytes.
• communicate() waits for the process to finish and captures all output—this is better than reading stdout/stderr directly to avoid deadlocks.

内容的提问来源于stack exchange，提问作者Tal