从磁盘读取文件
将本地文件转换为实时 MCP 资源。
从磁盘读取文件 是 CoddyKit 上的免费 MCP Academy 课时。 这是第 3 节课，共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 MCP Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 MCP Academy 课程共包含 4 节课。
本课时的部分内容尚未翻译，以英文显示。
From Fixed to Live
Returning a hardcoded string is fine, but real servers expose actual files. You can read a file from disk and serve its contents live.
Read Inside the Handler
Your resource function simply opens the file and returns its text. Because it runs on each request, the client always gets the current content. 📂
A Basic File Resource
Open the file, read it, and return the string. The resource now reflects whatever is saved on disk at read time.
@mcp.resource("file:///notes.txt")
def notes():
with open("notes.txt") as f:
return f.read()Use Pathlib Cleanly
The pathlib library reads small files in one line and handles paths safely across systems, which keeps your handler short and clear.
from pathlib import Path
@mcp.resource("file:///notes.txt")
def notes():
return Path("notes.txt").read_text()Handle Missing Files
A file can vanish or be renamed. Wrap the read so a missing file returns a clear error message instead of crashing the server.
try:
return Path(p).read_text()
except FileNotFoundError:
raise ValueError("File not found")Mind the Encoding
Text files have an encoding. Read with utf-8 explicitly so accented and non-English characters survive the trip to the model.
Path("notes.txt").read_text(encoding="utf-8")Watch the File Size
Returning a huge file floods the model with tokens and may hit limits. Keep served files small, or read only the part the model truly needs.
Never Trust the Path
If a path comes from input, an attacker could request files outside your folder. Always confine reads to a safe base directory you control.
Resolve Within a Base
Compute an absolute path and check it stays inside your allowed root. This blocks path traversal tricks like climbing up with dot-dot.
base = Path("data").resolve()
target = (base / name).resolve()
if base not in target.parents: raise ValueError("Denied")Read-Only by Nature
Resources only read; they never write. Serving a file as a resource exposes its contents without ever letting the model modify the file.
Verify the Live Read
Change the file on disk, then read the URI again. Seeing the new text proves your server reads live rather than caching stale content.
Quick Check
Security check on serving files.
Recap
Read a file inside the handler so content stays live. Set utf-8, handle missing files, watch size, and confine paths to a safe root. ✅
常见问题解答
「从磁盘读取文件」课时是免费的吗？
是的 — 「从磁盘读取文件」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 MCP Academy 课程的其余内容，请升级到 CoddyKit PRO。 MCP Academy 课程共包含 4 节课。
「从磁盘读取文件」这节课中我会学到什么？
将本地文件转换为实时 MCP 资源。 你通过在浏览器中直接运行的动手代码来练习 MCP Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 MCP Academy 需要有经验吗？
无需任何先前经验。CoddyKit 上的 MCP Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。 这是第 3 节课，共 4 节。
「从磁盘读取文件」课时需要多长时间？
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。
我能在这节 MCP Academy 课中编写并运行代码吗？
能。每节 MCP Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。