## Summary
* **What is the goal of this PR?** Fix KOReader sync failing on HTTPS
servers due to TLS out-of-memory on ESP32-C3
* **What changes are included?**
- Replace `WiFiClientSecure`/`HTTPClient` with `esp_http_client`
(ESP-IDF native API) for all KOSync HTTP requests
- Use 2KB TLS buffers instead of the default 16KB — KOSync payloads are
tiny JSON (<1KB), so this is more than sufficient
- Use `esp_crt_bundle_attach` for proper TLS certificate verification
(replaces `setInsecure()`)
- Strip trailing slashes from server URL to prevent double-slash in API
paths (e.g. `https://server.com//users/auth`)
- Add `lastHttpCode` static field for diagnostics
- Add free heap logging to help debug memory issues
### Problem
The ESP32-C3 has ~46KB free heap after WiFi is initialized.
`WiFiClientSecure` allocates 16KB for TLS RX + 16KB for TLS TX = 32KB
just for the TLS buffers, leaving almost no room for the actual TLS
handshake (which needs additional dynamic allocations). This causes
KOReader sync to:
1. Fail silently with network errors on HTTPS servers (including the
default `sync.koreader.rocks`)
2. Occasionally crash with heap exhaustion
### Solution
`esp_http_client` (the ESP-IDF native HTTP client) allows configuring
`buffer_size` and `buffer_size_tx` independently. Setting both to 2KB
(total 4KB) leaves plenty of heap for the TLS handshake while still
being sufficient for KOSync's small JSON payloads.
This also fixes the `setInsecure()` anti-pattern —
`esp_crt_bundle_attach` provides proper certificate verification using
the ESP-IDF's built-in CA bundle, so credentials and reading history are
no longer sent over unverified TLS connections.
### Files changed
| File | Change |
|------|--------|
| `lib/KOReaderSync/KOReaderSyncClient.cpp` | Replace
WiFiClientSecure/HTTPClient with esp_http_client; add ResponseBuffer,
base64 encoder, createClient helper |
| `lib/KOReaderSync/KOReaderSyncClient.h` | Add `lastHttpCode` static
field |
| `lib/KOReaderSync/KOReaderCredentialStore.cpp` | Strip trailing
slashes from base URL |
## Additional Context
Tested on a CrossPoint X4 (ESP32-C3 with 4MB flash). Before this change,
KOSync auth to `sync.koreader.rocks` (HTTPS) would fail ~80% of the
time. After: works reliably.
The `base64Encode` helper is needed because `esp_http_client` doesn't
have a built-in `setAuthorization()` method like `HTTPClient` does. This
is used for the HTTP Basic Auth header required by Calibre-Web-Automated
KOSync servers.
Fixes#581
---
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it helps set the right
context for reviewers.
Did you use AI tools to help write this code? _**PARTIALLY**_ AI
assisted with the esp_http_client migration pattern and base64 encoder.
The root cause analysis (TLS buffer OOM) and solution design were
manual.
---------
Co-authored-by: trilwu <trilwu@users.noreply.github.com>
Co-authored-by: Justin Mitchell <justin@jmitch.com>
## Summary
* Definition and use of a central LOG function, that can later be
extended or completely be removed (for public use where debugging
information may not be required) to save flash by suppressing the
-DENABLE_SERIAL_LOG like in the slim branch
* **What changes are included?**
## Additional Context
* By using the central logger the usual:
```
#include <HardwareSerial.h>
...
Serial.printf("[%lu] [WCS] Obfuscating/deobfuscating %zu bytes\n", millis(), data.size());
```
would then become
```
#include <Logging.h>
...
LOG_DBG("WCS", "Obfuscating/deobfuscating %zu bytes", data.size());
```
You do have ``LOG_DBG`` for debug messages, ``LOG_ERR`` for error
messages and ``LOG_INF`` for informational messages. Depending on the
verbosity level defined (see below) soe of these message types will be
suppressed/not-compiled.
* The normal compilation (default) will create a firmware.elf file of
42.194.356 bytes, the same code via slim will create 42.024.048 bytes -
170.308 bytes less
* Firmware.bin : 6.469.984 bytes for default, 6.418.672 bytes for slim -
51.312 bytes less
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? _NO_
---------
Co-authored-by: Xuan Son Nguyen <son@huggingface.co>
## Summary
* **What is the goal of this PR?** Provide support to koreader sync
server embedded in the popular *Calibre Web Automated* self-hosted
digital library solution.
* **What changes are included?**
* Trivial addition of **HTTP Basic Auth (RFC 7617) header** to
`lib/KOReaderSync/KOReaderSyncClient.cpp`
## Additional Context
None
---
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? _**NO**_
---------
Co-authored-by: drbourbon <fabio@MacBook-Air-di-Fabio.local>
## Summary
- Adds KOReader progress sync integration, allowing CrossPoint to sync
reading positions with other
KOReader-compatible devices
- Stores credentials securely with XOR obfuscation
- Uses KOReader's partial MD5 document hashing for cross-device book
matching
- Syncs position via percentage with estimated XPath for compatibility
# Features
- Settings: KOReader Username, Password, and Authenticate options
- Sync from chapters menu: "Sync Progress" option appears when
credentials are configured
- Bidirectional sync: Can apply remote progress or upload local progress
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
