feat: Add docs for DownloadHandler #4309
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AI Language Review |
mshabarov
commented
May 14, 2025
Comment on lines
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| == Using Custom Servlet and Request Parameters | ||
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| You can create a custom servlet which handles "image" as a relative URL: | ||
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| [source,java] | ||
| ---- | ||
| @WebServlet(urlPatterns = "/image", name = "DynamicContentServlet") | ||
| public class DynamicContentServlet extends HttpServlet { | ||
| @Override | ||
| protected void doGet(HttpServletRequest req, HttpServletResponse resp) | ||
| throws ServletException, IOException { | ||
| resp.setContentType("image/svg+xml"); | ||
| String name = req.getParameter("name"); | ||
| if (name == null) { | ||
| name = ""; | ||
| } | ||
| String svg = "<?xml version='1.0' encoding='UTF-8' standalone='no'?>" | ||
| + "<svg xmlns='http://www.w3.org/2000/svg' " | ||
| + "xmlns:xlink='http://www.w3.org/1999/xlink'>" | ||
| + "<rect x='10' y='10' height='100' width='100' " | ||
| + "style=' fill: #90C3D4'/><text x='30' y='30' fill='red'>" | ||
| + name + "</text>" + "</svg>"; | ||
| resp.getWriter().write(svg); | ||
| } | ||
| } | ||
| ---- |
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This is from the old article, I'd keep it just in case if someone is interested in a low level servlet way of downloading a content.
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Pull Request Overview
This PR adds comprehensive documentation for the new DownloadHandler API in Vaadin 24.8, including multiple usage scenarios and API customization examples.
- Removed the legacy dynamic content documentation.
- Added detailed documentation for DownloadHandler covering classpath resource downloads, file system downloads, dynamic InputStream downloads, progress tracking, and custom download handlers.
Reviewed Changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| articles/flow/advanced/dynamic-content.adoc | Legacy documentation removed. |
| articles/flow/advanced/downloads.adoc | New documentation added for the DownloadHandler API. |
Comments suppressed due to low confidence (1)
articles/flow/advanced/downloads.adoc:241
- [nitpick] The class name 'LinkWithM5Validation' is ambiguous; consider renaming it to something more descriptive, such as 'LinkWithChecksumValidation'.
private static class LinkWithM5Validation extends Anchor {
Co-authored-by: Copilot <[email protected]>
mshabarov
commented
May 15, 2025
Comment on lines
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| MessageDigest md5 = MessageDigest.getInstance("MD5"); | ||
| byte[] digest = md5.digest(data); | ||
| String base64Md5 = Base64.getEncoder().encodeToString(digest); | ||
| event.getResponse().setHeader("Content-MD5", base64Md5); |
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This example with calculating MD5 checksum and checking it on the client isn't perhaps a realistic case. I'd think of a better case for when setting a header is useful in download handler, feel free to share a better example if you have any.
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Adds a documentation for new API for handling downloads in Vaadin 24.8.
Fixes #4303