你大概可以跳過這段。

這裡是有關 FastAPI 內部技術細節。

如果你有相當多的技術背景（例如協程、執行緒、阻塞等），並且對 FastAPI 如何處理 `async def` 與常規 `def` 感到好奇，請繼續閱讀。

///

### 路徑操作函数

當你使用 `def` 而不是 `async def` 宣告*路徑操作函式*時，該函式會在外部的執行緒池（threadpool）中執行，然後等待結果，而不是直接呼叫（因為這樣會阻塞伺服器）。

如果你來自於其他不以這種方式運作的非同步框架，而且你習慣於使用普通的 `def` 定義僅進行簡單計算的*路徑操作函式*，目的是獲得微小的性能增益（大約 100 奈秒），請注意，在 FastAPI 中，效果會完全相反。在這些情況下，最好使用 `async def`除非你的*路徑操作函式*執行阻塞的 <abbr title="輸入/輸出：磁碟讀寫或網路通訊">I/O</abbr> 的程式碼。

    private static final long serialVersionUID = 1L;

    /**
     * Resource type that caused the error
     */
    public enum ResourceType {
        FILE_HANDLE, CONNECTION, MEMORY, DISK_SPACE, QUOTA, LOCK, BUFFER, THREAD_POOL
    }

    private final ResourceType resourceType;
    private final long availableResources;
    private final long requestedResources;

    /**
     * Creates a resource exception
     *

            { "aliases", "allocation", "count", "fielddata", "health", "indices", "master", "nodeattrs", "nodes", "pending_tasks",
                    "plugins", "recovery", "repositories", "thread_pool", "shards", "segments", "snapshots", "templates" };

    // ===================================================================================

    * This allows adding extra code after a dependency is done. It can be used, for example, to close database connections.
    * Dependencies with `yield` can be normal or `async`, **FastAPI** will run normal dependencies in a threadpool.
    * They can be combined with normal dependencies.
    * It's possible to have arbitrary trees/levels of dependencies with `yield` and exit steps are handled in the correct order automatically.

# common

# Default script for the crawler (e.g., groovy).
crawler.default.script=groovy
# Number of threads for HTTP crawling.
crawler.http.thread_pool.size=0
# Serializer type for crawler data (e.g., kryo).
crawler.data.serializer=kryo
# Maximum length of site name in documents.
crawler.document.max.site.length=100
# Encoding for site names in documents.

    /**
     * Get the value for the key 'crawler.http.thread_pool.size'. <br>
     * The value is, e.g. 0 <br>
     * comment: Number of threads for HTTP crawling.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getCrawlerHttpThreadPoolSize();

    /**
     * Get the value for the key 'crawler.http.thread_pool.size' as {@link Integer}. <br>