add draft blog post for mitmproxy 12

Author: mhils

src/content/posts/releases/mitmproxy-12/index.md

@@ -0,0 +1,78 @@
+---
+title: "Mitmproxy 12: Interactive Contentviews"
+date: 2025-04-22
+weight: 10
+tags:
+  - releases
+authors:
+  - maximilian-hils
+---
+
+We're thrilled to announce the release of mitmproxy 12, introducing *Interactive Contentviews*!
+It's now possible to modify the prettified representation of binary protocols, 
+which is then re-encoded back into the original binary format.
+
+<!--more-->
+
+# Interactive Contentviews
+
+First [introduced in 2011], the ability to pretty-print HTTP message bodies has been a mitmproxy feature 
+since the very early days.
+The functionality later became a shared component between the console and web interfaces 
+in 2015 ([#764]), soon followed by support for custom user-provided views ([#833]). 
+However, these views were always read-only; editing binary protocols meant changing raw bytes.
+
+Now, with interactive contentviews, you can directly edit the human-readable, prettified representation,
+and mitmproxy will handle the task of re-encoding it back into its binary form.
+This dramatically simplifies tinkering with unknown binary protocols such as gRPC/Protobuf or MsgPack.
+
+(protobuf gif)
+
+[introduced in 2011]: https://github.com/mitmproxy/mitmproxy/commit/93ef691badcdaa1b7a5801eb40982c69f9b89534
+[#764]: https://github.com/mitmproxy/mitmproxy/pull/764
+[#833]: https://github.com/mitmproxy/mitmproxy/pull/832
+
+## Spotlight: gRPC & Protobuf
+
+The prime example of interactive contentviews is our enhanced gRPC and Protobuf support.
+You can now modify Protobuf messages directly within mitmproxy, 
+whether you have access to the Protobuf definitions (`.proto` files) or not.
+
+- **Known Protobufs:** Set the new [`protobuf_definitions`] option in mitmproxy to your `.proto` file 
+  and edit fields by name.
+- **Unknown Protobufs:** You won't have field names, but you can still interactively modify primitive values 
+  (strings, integers, nested messages) and mitmproxy will re-encode your changes.
+
+(screenshot of example gRPC with and without definitions)
+
+[`protobuf_definitions`]: https://docs.mitmproxy.org/stable/concepts/options/#protobuf_definitions
+
+## New Contentview API
+
+Underpinning this interactivity is a revamped and drastically simpler Contentview API. 
+Instead of returning a list of lines with inline markup, 
+the new [`prettify`] method simply takes `bytes` and returns `str`, and then [`reencode`] does the reverse.
+As a simple example, here's what mitmproxy's builtin contentview for DNS messages looks like:
+
+(DNS example snippet)
+
+Check out our [new contentview documentation] for more examples!
+
+[`prettify`]: https://docs.mitmproxy.org/stable/api/mitmproxy/contentviews.html#Contentview.prettify
+[`reencode`]: https://docs.mitmproxy.org/stable/api/mitmproxy/contentviews.html#Contentview.reencode
+[new contentview documentation]: https://docs.mitmproxy.org/stable/addons/contentviews/
+
+## Rust-based Contentviews
+
+With the new API, we're also increasing our investment in Rust to deliver safe and performant contentviews:
+
+- **Built-in contentviews can now also be written in Rust.** In fact, the gRPC, Protobuf, and MsgPack contentviews
+  are all Rust-based. The [MsgPack implementation] is a great example to demonstrate how access to the crates.io 
+  ecosystem and the [serde] framework in particular makes writing contentviews super easy.
+- **Syntax highlighting is now done in Rust.** For mitmproxy and mitmweb, the [mitmproxy-highlight] crate does all the
+  work (using [tree-sitter] under the hood).
+
+[MsgPack implementation]: https://github.com/mitmproxy/mitmproxy_rs/blob/5ec05682b122a2c1ee6584b4fe57a698eef573fd/mitmproxy-contentviews/src/msgpack.rs
+[serde]: https://serde.rs/
+[mitmproxy-highlight]: https://github.com/mitmproxy/mitmproxy_rs/tree/main/mitmproxy-highlight
+[tree-sitter]: https://tree-sitter.github.io/tree-sitter/