media_download Directory Reference

Directory dependency graph for media_download:

Directories
	inc
	src

Detailed Description

The RA8 composition root for the reusable media-transfer path: an HTTPS source reached over the ESP32-C6 on Pmod1, landing as a strictly-validated .rabook on a micro-SD card in Pmod2.

One run opens the ESP-hosted C6 link and joins the configured station, mounts the card's existing FAT volume without formatting it, creates sd:/BOOKS when absent (and refuses a non-directory collision), then streams the HTTPS response body in bounded RPC pulls. The body is either a prebuilt .rabook or – in source-image mode – one bounded encoded image which the RA8 decodes, normalizes, emits as a one-page RABOOK1 book and wraps as an RBKC random-access container. That mode is conversion, not relabeling, and its new bytes go through the same strict validator as everything else.

The artifact is hashed independently, its private stage is closed, and every RBKC zlib stream plus the inner RABOOK1 structure is strictly validated before the file is published through the VFS no-replace rename. The app then reopens the committed file, revalidates it, reads metadata, and demand-loads the first exact inflated chunk.

The transfer, the inflated chunk size and the chunk-table length are all bounded. The table, compressed staging, inflated chunk and strict-validation scratch live in external SDRAM. First-party code uses no heap and no stdio; miniz is built with MINIZ_NO_MALLOC and MINIZ_NO_STDIO.

Publication is deliberately create-new: a second successful run with the same destination refuses to replace the existing book, which must be removed through an authorized maintenance path first. Native FAT/exFAT does not claim a power-loss-atomic rename or a durable barrier, and this app does not invent those guarantees.

Runtime configuration

Every build is credential-free. After boot the image prints ra8_net_provision: READY v1 and accepts exactly one bounded packet over the debug UART:

RA8NET1:<ssid_hex>:<psk_hex>:<url_hex>

Unlike the join and camera examples, this app requires the URL field. Invalid, missing, or oversized input fails before storage publication or a media RPC. Received bytes are never echoed. Wi-Fi fields are erased after association and the URL is erased after the transfer returns, so neither compiler metadata nor firmware artifacts contain runtime configuration.

Blocked on

Physical mixed-image HIL. The configured cross-build proves the board, C6, SD / FAT / VFS, strict reader, source formatter and SHA types compose with fixed storage, and the matching ESP32-C6 image compiles and links from current sources with post-link checks for the strong media handler and the component ABI marker. Host tests exercise success, transport corruption, coherent-but-invalid RBKC, no-stage cleanup and exact readback. What is missing is a run on the board proving success and failure cleanup.