chore(express-partial-content): move source files

packages/express-partial-content/src/createPartialContentHandler.ts

@@ -0,0 +1,60 @@
+import { Request, Response } from "express";
+import { parseRangeHeader } from "./parseRangeHeader";
+import { RangeParserError } from "./RangeParserError";
+import { Logger } from "./Logger";
+import { ContentProvider } from "./ContentProvider";
+import { ContentDoesNotExistError } from "./ContentDoesNotExistError";
+import {
+  getRangeHeader,
+  setContentRangeHeader,
+  setContentTypeHeader,
+  setContentDispositionHeader,
+  setAcceptRangesHeader,
+  setContentLengthHeader,
+  setCacheControlHeaderNoCache
+} from "./utils";
+export function createPartialContentHandler(contentProvider: ContentProvider, logger: Logger) {
+  return async function handler(req: Request, res: Response) {
+    let content;
+    try {
+      content = await contentProvider(req);
+    } catch (error) {
+      logger.debug("createPartialContentHandler: ContentProvider threw exception: ", error);
+      if (error instanceof ContentDoesNotExistError) {
+        return res.status(404).send(error.message);
+      }
+      return res.sendStatus(500);
+    }
+    let { getStream, mimeType, fileName, totalSize } = content;
+    const rangeHeader = getRangeHeader(req);
+    let range;
+    try {
+      range = parseRangeHeader(rangeHeader, totalSize, logger);
+    } catch (error) {
+      logger.debug(`createPartialContentHandler: parseRangeHeader error: `, error);
+      if (error instanceof RangeParserError) {
+        setContentRangeHeader(null, totalSize, res);
+        return res.status(416).send(`Invalid value for Range: ${rangeHeader}`);
+      }
+      return res.sendStatus(500);
+    }
+    setContentTypeHeader(mimeType, res);
+    setContentDispositionHeader(fileName, res);
+    setAcceptRangesHeader(res);
+    // If range is not specified, or the file is empty, return the full stream
+    if (range === null) {
+      logger.debug("createPartialContentHandler: No range found, returning full content.");
+      setContentLengthHeader(totalSize, res);
+      return getStream().pipe(res);
+    }
+    setContentRangeHeader(range, totalSize, res);
+    let { start, end } = range;
+    setContentLengthHeader(start === end ? 0 : end - start + 1, res);
+    setCacheControlHeaderNoCache(res);
+    // Return 206 Partial Content status
+    logger.debug("createPartialContentHandler: Returning partial content for range: ", JSON.stringify(range));
+    res.status(206);
+
+    return getStream(range).pipe(res);
+  };
+}