Our esp32 consistently dropped the last few packets of the TCP transfer
in the old implementation. Only about 1/5 transfers would complete. I've
refactored that entire system into an actual Calibre Device Plugin that
basically uses the exact same system as the web server's file transfer
protocol. I kept them separate so that we don't muddy up the existing
file transfer stuff even if it's basically the same at the end of the
day I didn't want to limit our ability to change it later.
I've also added basic auth to OPDS and renamed that feature to OPDS
Browser to just disassociate it from Calibre.
---------
Co-authored-by: Arthur Tazhitdinov <lisnake@gmail.com>
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
* **What is the goal of this PR?** Fix WiFi file transfer stability
issues (especially crashes during uploads) and improve upload speed via
WebSocket binary protocol. File transfers now don't really crash as
much, if they do it recovers and speed has gone form 50KB/s to 300+KB/s.
* **What changes are included?**
- **WebSocket upload support** - Adds WebSocket binary protocol for file
uploads, achieving faster speeds 335 KB/s vs HTTP multipart)
- **Watchdog stability fixes** - Adds `esp_task_wdt_reset()` calls
throughout upload path to prevent watchdog timeouts during:
- File creation (FAT allocation can be slow)
- SD card write operations
- HTTP header parsing
- WebSocket chunk processing
- **4KB write buffering** - Batches SD card writes to reduce I/O
overhead
- **WiFi health monitoring** - Detects WiFi disconnection in STA mode
and exits gracefully
- **Improved handleClient loop** - 500 iterations with periodic watchdog
resets and button checks for responsiveness
- **Progress bar improvements** - Fixed jumping/inaccurate progress by
capping local progress at 95% until server confirms completion
- **Exit button responsiveness** - Button now checked inside the
handleClient loop every 64 iterations
- **Reduced exit delays** - Decreased shutdown delays from ~850ms to
~140ms
**Files changed:**
- `platformio.ini` - Added WebSockets library dependency
- `CrossPointWebServer.cpp/h` - WebSocket server, upload buffering,
watchdog resets
- `CrossPointWebServerActivity.cpp` - WiFi monitoring, improved loop,
button handling
- `FilesPage.html` - WebSocket upload JavaScript with HTTP fallback
## Additional Context
- WebSocket uses 4KB chunks with backpressure management to prevent
ESP32 buffer overflow
- Falls back to HTTP automatically if WebSocket connection fails
- The main bottleneck now is SD card write speed (~44% of transfer
time), not WiFi
- STA mode was more prone to crashes than AP mode due to external
network factors; WiFi health monitoring helps detect and handle
disconnections gracefully
---
### AI Usage
Did you use AI tools to help write this code? _**YES**_ Claude did it
ALL, I have no idea what I am doing, but my books transfer fast now.
---------
Co-authored-by: Claude <noreply@anthropic.com>
## Summary
* **What is the goal of this PR?** Adds WiFi Access Point (AP) mode
support for File Transfer, allowing the device to create its own WiFi
network that users can connect to directly - useful when no existing
WiFi network is available. And in my experience is faster when the
device is right next to your laptop (but maybe further from your wifi)
* **What changes are included?**
- New `NetworkModeSelectionActivity` - an interstitial screen asking
users to choose between:
- "Join a Network" - connects to an existing WiFi network (existing
behavior)
- "Create Hotspot" - creates a WiFi access point named
"CrossPoint-Reader"
- Modified `CrossPointWebServerActivity` to:
- Launch the network mode selection screen before proceeding
- Support starting an Access Point with mDNS (`crosspoint.local`) and
DNS server for captive portal behavior
- Display appropriate connection info for both modes
- Modified `CrossPointWebServer` to support starting when WiFi is in AP
mode (not just STA connected mode)
## Additional Context
* **AP Mode Details**: The device creates an open WiFi network named
"CrossPoint-Reader". Once connected, users can access the file transfer
page at `http://crosspoint.local/` or `http://192.168.4.1/`
* **DNS Captive Portal**: A DNS server redirects all domain requests to
the device's IP, enabling captive portal behavior on some devices
* **mDNS**: Hostname resolution via `crosspoint.local` is enabled for
both AP and STA modes
* **No breaking changes**: The "Join a Network" option preserves the
existing WiFi connection flow
* **Memory impact**: Minimal - the AP mode uses roughly the same
resources as STA mode
## Summary
* HTML files are now static, streamed directly to the client without
modification
* For any dynamic values, load via JSON APIs
* For files page, we stream the JSON content as we scan the directory to
avoid holding onto too much data
## Additional details
* We were previously building up a very large string all generated on
the X4 directly, we should be leveraging the browser
* Fixes https://github.com/daveallie/crosspoint-reader/issues/94
