feat: add caldav support

There's quite a lot here - because caldav support needed some fair
refactoring/etc. to get working. Happily after this I can commit a
little more incrementally as I'll be able to deploy what I have here...

...due to needing a password, I don't have any caldav test data- the
format for making a dav subscription is something like so:

INSERT INTO dav_connections ("id", "url", "username", "password") VALUES ('00069420-74d2-4ba8-85d6-4fc679810c02', <base URI>, <username>, <password>);
INSERT INTO subscriptions ("id", "reference", "dav_connection") VALUES ('12a89516-65f7-4874-8449-671b7c8444af', '/my/href/of/my/calendar/', '00069420-74d2-4ba8-85d6-4fc679810c02');

It's worth noting that - I believe - we return some minorly noncompliant
data for colors (i.e. I think the list of values that are supported for
calendar colors is greater than the list of values supported for, say,
event colors). Happily, I guess, after I wrote the caldav colors feature
I found out that Google Calendar doesn't support ical colors anyway. I
also then didn't write the feature for direct ical subscriptions so...
...another time, maybe.

Cargo.lock

···
 version = 4
 
 [[package]]
+name = "adler2"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "320119579fcad9c21884f5c4861d16174d0e06250625266f50fe6898340abefa"
+
+[[package]]
 name = "aho-corasick"
 version = "1.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8e60d3430d3a69478ad0993f19238d2df97c507009a52b3c10addcd7f6bcb916"
 dependencies = [
  "memchr",
+]
+
+[[package]]
+name = "alloc-no-stdlib"
+version = "2.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc7bb162ec39d46ab1ca8c77bf72e890535becd1751bb45f64c597edb4c8c6b3"
+
+[[package]]
+name = "alloc-stdlib"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94fb8275041c72129eb51b7d0322c29b8387a0386127718b096429201a5d6ece"
+dependencies = [
+ "alloc-no-stdlib",
 ]
 
 [[package]]
···
 checksum = "a23eb6b1614318a8071c9b2521f36b424b2c83db5eb3a0fead4a6c0809af6e61"
 
 [[package]]
+name = "async-compression"
+version = "0.4.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a89bce6054c720275ac2432fbba080a66a2106a44a1b804553930ca6909f4e0"
+dependencies = [
+ "compression-codecs",
+ "compression-core",
+ "futures-core",
+ "pin-project-lite",
+ "tokio",
+]
+
+[[package]]
 name = "async-lock"
 version = "3.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 checksum = "c08606f8c3cbf4ce6ec8e28fb0014a2c086708fe954eaa885384a6165172e7e8"
 
 [[package]]
+name = "aws-lc-rs"
+version = "1.14.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "879b6c89592deb404ba4dc0ae6b58ffd1795c78991cbb5b8bc441c48a070440d"
+dependencies = [
+ "aws-lc-sys",
+ "zeroize",
+]
+
+[[package]]
+name = "aws-lc-sys"
+version = "0.32.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "107a4e9d9cab9963e04e84bb8dee0e25f2a987f9a8bad5ed054abd439caa8f8c"
+dependencies = [
+ "bindgen",
+ "cc",
+ "cmake",
+ "dunce",
+ "fs_extra",
+]
+
+[[package]]
 name = "axum"
 version = "0.8.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 checksum = "55248b47b0caf0546f7988906588779981c43bb1bc9d0c44087278f80cdb44ba"
 
 [[package]]
+name = "bindgen"
+version = "0.72.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "993776b509cfb49c750f11b8f07a46fa23e0a1386ffc01fb1e7d343efc387895"
+dependencies = [
+ "bitflags",
+ "cexpr",
+ "clang-sys",
+ "itertools 0.13.0",
+ "log",
+ "prettyplease",
+ "proc-macro2",
+ "quote",
+ "regex",
+ "rustc-hash",
+ "shlex",
+ "syn",
+]
+
+[[package]]
 name = "bitflags"
 version = "2.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 ]
 
 [[package]]
+name = "brotli"
+version = "8.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4bd8b9603c7aa97359dbd97ecf258968c95f3adddd6db2f7e7a5bef101c84560"
+dependencies = [
+ "alloc-no-stdlib",
+ "alloc-stdlib",
+ "brotli-decompressor",
+]
+
+[[package]]
+name = "brotli-decompressor"
+version = "5.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "874bb8112abecc98cbd6d81ea4fa7e94fb9449648c93cc89aa40c81c24d7de03"
+dependencies = [
+ "alloc-no-stdlib",
+ "alloc-stdlib",
+]
+
+[[package]]
 name = "bumpalo"
 version = "3.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
  "anyhow",
  "axum",
  "console_error_panic_hook",
+ "fast-dav-rs",
  "icalendar",
  "leptos",
  "leptos_axum",
  "leptos_meta",
  "leptos_router",
  "reqwest",
+ "rustls",
  "sqlx",
  "tokio",
  "uuid",
···
 checksum = "739eb0f94557554b3ca9a86d2d37bebd49c5e6d0c1d2bda35ba5bdac830befc2"
 dependencies = [
  "find-msvc-tools",
+ "jobserver",
+ "libc",
  "shlex",
 ]
 
 [[package]]
+name = "cexpr"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6fac387a98bb7c37292057cffc56d62ecb629900026402633ae9160df93a8766"
+dependencies = [
+ "nom 7.1.3",
+]
+
+[[package]]
 name = "cfg-if"
 version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 ]
 
 [[package]]
+name = "clang-sys"
+version = "1.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b023947811758c97c59bf9d1c188fd619ad4718dcaa767947df1cadb14f39f4"
+dependencies = [
+ "glob",
+ "libc",
+ "libloading",
+]
+
+[[package]]
+name = "cmake"
+version = "0.1.54"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e7caa3f9de89ddbe2c607f4101924c5abec803763ae9534e4f4d7d8f84aa81f0"
+dependencies = [
+ "cc",
+]
+
+[[package]]
 name = "codee"
 version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 checksum = "2550f75b8cfac212855f6b1885455df8eaee8fe8e246b647d69146142e016084"
 
 [[package]]
+name = "compression-codecs"
+version = "0.4.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef8a506ec4b81c460798f572caead636d57d3d7e940f998160f52bd254bf2d23"
+dependencies = [
+ "brotli",
+ "compression-core",
+ "flate2",
+ "memchr",
+ "zstd",
+ "zstd-safe",
+]
+
+[[package]]
+name = "compression-core"
+version = "0.4.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e47641d3deaf41fb1538ac1f54735925e275eaf3bf4d55c81b137fba797e5cbb"
+
+[[package]]
 name = "concurrent-queue"
 version = "2.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "91e195e091a93c46f7102ec7818a2aa394e1e1771c3ab4825963fa03e45afb8f"
+dependencies = [
+ "core-foundation-sys",
+ "libc",
+]
+
+[[package]]
+name = "core-foundation"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b2a6cd9ae233e7f62ba4e9353e81a88df7fc8a5987b8d445b4d90c879bd156f6"
 dependencies = [
  "core-foundation-sys",
  "libc",
···
 checksum = "19d374276b40fb8bbdee95aef7c7fa6b5316ec764510eb64b8dd0e2ed0d7e7f5"
 
 [[package]]
+name = "crc32fast"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9481c1c90cbf2ac953f07c8d4a58aa3945c425b7185c9154d67a65e4230da511"
+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
 name = "crossbeam-queue"
 version = "0.3.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 checksum = "669a445ee724c5c69b1b06fe0b63e70a1c84bc9bb7d9696cd4f4e3ec45050408"
 
 [[package]]
+name = "dunce"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "92773504d58c093f6de2459af4af33faa518c13451eb8f2b5698ed3d36e7c813"
+
+[[package]]
 name = "either"
 version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 ]
 
 [[package]]
+name = "fast-dav-rs"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51f55d1a4f112e8df314be4b39dabee93c1d6d42a27af3cd0699be4315bc0cdf"
+dependencies = [
+ "anyhow",
+ "async-compression",
+ "base64",
+ "bytes",
+ "futures",
+ "futures-util",
+ "http-body-util",
+ "hyper",
+ "hyper-rustls",
+ "hyper-util",
+ "quick-xml",
+ "tokio",
+ "tokio-util",
+]
+
+[[package]]
 name = "fastrand"
 version = "2.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 checksum = "52051878f80a721bb68ebfbc930e07b65ba72f2da88968ea5c06fd6ca3d3a127"
 
 [[package]]
+name = "flate2"
+version = "1.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bfe33edd8e85a12a67454e37f8c75e730830d83e313556ab9ebf9ee7fbeb3bfb"
+dependencies = [
+ "crc32fast",
+ "miniz_oxide",
+]
+
+[[package]]
 name = "flume"
 version = "0.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 dependencies = [
  "percent-encoding",
 ]
+
+[[package]]
+name = "fs_extra"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42703706b716c37f96a77aea830392ad231f44c9e9a67872fa5548707e11b11c"
 
 [[package]]
 name = "futures"
···
 ]
 
 [[package]]
+name = "glob"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0cc23270f6e1808e30a928bdc84dea0b9b4136a8bc82338574f23baf47bbd280"
+
+[[package]]
 name = "gloo-net"
 version = "0.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
  "http",
  "hyper",
  "hyper-util",
+ "log",
  "rustls",
+ "rustls-native-certs",
  "rustls-pki-types",
  "tokio",
  "tokio-rustls",
···
  "chrono",
  "chrono-tz",
  "iso8601",
- "nom",
+ "nom 8.0.0",
  "nom-language",
  "serde",
  "time",
···
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e1082f0c48f143442a1ac6122f67e360ceee130b967af4d50996e5154a45df46"
 dependencies = [
- "nom",
+ "nom 8.0.0",
+]
+
+[[package]]
+name = "itertools"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "413ee7dfc52ee1a4949ceeb7dbc8a33f2d6c088194d9f922fb8318faf1f01186"
+dependencies = [
+ "either",
 ]
 
 [[package]]
···
 version = "1.0.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4a5f13b858c8d314ee3e8f639011f7ccefe71f97f96e50151fb991f267928e2c"
+
+[[package]]
+name = "jobserver"
+version = "0.1.34"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9afb3de4395d6b3e67a780b6de64b51c978ecf11cb9a462c66be7d4ca9039d33"
+dependencies = [
+ "getrandom 0.3.4",
+ "libc",
+]
 
 [[package]]
 name = "js-sys"
···
  "cfg-if",
  "convert_case 0.8.0",
  "html-escape",
- "itertools",
+ "itertools 0.14.0",
  "leptos_hot_reload",
  "prettyplease",
  "proc-macro-error2",
···
 checksum = "2874a2af47a2325c2001a6e6fad9b16a53b802102b528163885171cf92b15976"
 
 [[package]]
+name = "libloading"
+version = "0.8.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d7c4b02199fee7c5d21a5ae7d8cfa79a6ef5bb2fc834d6e9058e89c825efdc55"
+dependencies = [
+ "cfg-if",
+ "windows-link 0.2.1",
+]
+
+[[package]]
 name = "libm"
 version = "0.2.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 ]
 
 [[package]]
+name = "minimal-lexical"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
+
+[[package]]
+name = "miniz_oxide"
+version = "0.8.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1fa76a2c86f704bdb222d66965fb3d63269ce38518b83cb0575fca855ebb6316"
+dependencies = [
+ "adler2",
+ "simd-adler32",
+]
+
+[[package]]
 name = "mio"
 version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
  "openssl-probe",
  "openssl-sys",
  "schannel",
- "security-framework",
+ "security-framework 2.11.1",
  "security-framework-sys",
  "tempfile",
 ]
···
 
 [[package]]
 name = "nom"
+version = "7.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d273983c5a657a70a3e8f2a01329822f3b8c8172b73826411a55751e404a0a4a"
+dependencies = [
+ "memchr",
+ "minimal-lexical",
+]
+
+[[package]]
+name = "nom"
 version = "8.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "df9761775871bdef83bee530e60050f7e54b1105350d6884eb0fb4f46c2f9405"
···
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2de2bc5b451bfedaef92c90b8939a8fff5770bdcc1fafd6239d086aab8fa6b29"
 dependencies = [
- "nom",
+ "nom 8.0.0",
 ]
 
 [[package]]
···
 ]
 
 [[package]]
+name = "quick-xml"
+version = "0.38.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42a232e7487fc2ef313d96dde7948e7a3c05101870d8985e4fd8d26aedd27b89"
+dependencies = [
+ "memchr",
+ "tokio",
+]
+
+[[package]]
 name = "quinn"
 version = "0.11.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 dependencies = [
  "dashmap",
  "guardian",
- "itertools",
+ "itertools 0.14.0",
  "or_poisoned",
  "paste",
  "reactive_graph",
···
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6a9586e9ee2b4f8fab52a0048ca7334d7024eef48e2cb9407e3497bb7cab7fa7"
 dependencies = [
+ "aws-lc-rs",
+ "log",
  "once_cell",
  "ring",
  "rustls-pki-types",
···
 ]
 
 [[package]]
+name = "rustls-native-certs"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9980d917ebb0c0536119ba501e90834767bffc3d60641457fd84a1f3fd337923"
+dependencies = [
+ "openssl-probe",
+ "rustls-pki-types",
+ "schannel",
+ "security-framework 3.5.1",
+]
+
+[[package]]
 name = "rustls-pki-types"
 version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e10b3f4191e8a80e6b43eebabfac91e5dcecebb27a71f04e820c47ec41d314bf"
 dependencies = [
+ "aws-lc-rs",
  "ring",
  "rustls-pki-types",
  "untrusted",
···
 checksum = "897b2245f0b511c87893af39b033e5ca9cce68824c4d7e7630b5a1d339658d02"
 dependencies = [
  "bitflags",
- "core-foundation",
+ "core-foundation 0.9.4",
+ "core-foundation-sys",
+ "libc",
+ "security-framework-sys",
+]
+
+[[package]]
+name = "security-framework"
+version = "3.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b3297343eaf830f66ede390ea39da1d462b6b0c1b000f420d0a83f898bbbe6ef"
+dependencies = [
+ "bitflags",
+ "core-foundation 0.10.1",
  "core-foundation-sys",
  "libc",
  "security-framework-sys",
···
  "digest",
  "rand_core 0.6.4",
 ]
+
+[[package]]
+name = "simd-adler32"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d66dc143e6b11c1eddc06d5c423cfc97062865baf299914ab64caa38182078fe"
 
 [[package]]
 name = "siphasher"
···
 checksum = "3c879d448e9d986b661742763247d3693ed13609438cf3d006f51f5368a5ba6b"
 dependencies = [
  "bitflags",
- "core-foundation",
+ "core-foundation 0.9.4",
  "system-configuration-sys",
 ]
 
···
  "futures",
  "html-escape",
  "indexmap",
- "itertools",
+ "itertools 0.14.0",
  "js-sys",
  "linear-map",
  "next_tuple",
···
  "quote",
  "syn",
 ]
+
+[[package]]
+name = "zstd"
+version = "0.13.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e91ee311a569c327171651566e07972200e76fcfe2242a4fa446149a3881c08a"
+dependencies = [
+ "zstd-safe",
+]
+
+[[package]]
+name = "zstd-safe"
+version = "7.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8f49c4d5f0abb602a93fb8736af2a4f4dd9512e36f7f570d66e65ff867ed3b9d"
+dependencies = [
+ "zstd-sys",
+]
+
+[[package]]
+name = "zstd-sys"
+version = "2.0.16+zstd.1.5.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "91e19ebc2adc8f83e43039e79776e3fda8ca919132d68a1fed6a5faca2683748"
+dependencies = [
+ "cc",
+ "pkg-config",
+]

Cargo.toml

···
 anyhow = "1.0.100"
 reqwest = { version = "0.12.24", features = ["rustls-tls-webpki-roots", "charset", "http2"], optional = true }
 icalendar = { version = "0.17.5", features = ["parser", "serde", "chrono-tz", "time",], optional = true }
+fast-dav-rs = { version = "0.1.0", optional = true }
+rustls = { version = "0.23.34", features = ["ring"], optional = true }
 
 [features]
 hydrate = [
···
 ]
 ssr = [
     "dep:axum",
+    "dep:fast-dav-rs",
     "dep:icalendar",
     "dep:leptos_axum",
     "dep:reqwest",
+    "dep:rustls",
     "dep:sqlx",
     "dep:tokio",
     "dep:uuid",

migrations/20251027071639_add-caldav.sql

···
+ALTER TABLE "subscriptions" RENAME COLUMN "url" TO "reference";
+ALTER TABLE "subscriptions" ADD COLUMN "dav_connection" uuid;
+
+CREATE TABLE "dav_connections" (
+  "id" uuid PRIMARY KEY,
+  "url" varchar NOT NULL,
+  "username" varchar,
+  "password" varchar
+);
+
+ALTER TABLE "subscriptions" ADD CONSTRAINT "subscription_dav_connection" FOREIGN KEY ("dav_connection") REFERENCES "dav_connections" ("id");

src/calendar.rs

···
 use std::ops::DerefMut;
-
 use axum::extract::Path;
+use fast_dav_rs::CalDavClient;
+use icalendar::Component;
 use leptos::prelude::ServerFnError;
 use leptos::server;
 use tokio::task::JoinSet;
···
 
 #[server]
 async fn events_by_calendar(id: Uuid) -> anyhow::Result<String, ServerFnError> {
-    let state = STATE.get().unwrap();
-
-    println!("{:?}", id);
+    let state = STATE.get().expect("Failed to get STATE - is it set yet?");
 
-    let subscription_urls = sqlx::query!(
-        "SELECT url FROM subscriptions
+    let subscriptions = sqlx::query!(
+        r#"SELECT subscriptions.reference, dav_connections.url as "dav_connection_url?", dav_connections.username, dav_connections.password FROM subscriptions
          JOIN calendars_subscriptions on subscriptions.id = calendars_subscriptions.subscriptions_id
          JOIN calendars on calendars.id = calendars_subscriptions.calendars_id
-         WHERE calendars.id = $1",
+         LEFT JOIN dav_connections on subscriptions.dav_connection = dav_connections.id
+         WHERE calendars.id = $1"#,
         id
     ).fetch_all(state.sqlx_connection.lock().await.deref_mut()).await?;
 
-    println!("{:#?}", subscription_urls);
-
     let mut requests = JoinSet::new();
 
-    for url in subscription_urls {
+    for subscription in subscriptions {
         requests.spawn((async || {
-            let result = state.reqwest_client.get(url.url).send().await;
+            if let (Some(dav_connection_url), username, password) = (subscription.dav_connection_url, subscription.username, subscription.password) {
+                // fast_dav_rs client doesn't follow redirects, so we must use reqwest to check first so, e.g., stalwart .well-known/caldav URLs work
+                let base_url = state.reqwest_client.head(&dav_connection_url).send().await
+                        .and_then(|response| Ok(response.url().to_string()))
+                        .unwrap_or_else(|_| dav_connection_url);
+
+                let Ok(client) = CalDavClient::new(&base_url, username.as_deref(), password.as_deref()) else {
+                    return None
+                };
+                
+                return get_dav_calendar(client, &subscription.reference).await
+            }
+            let result = state.reqwest_client.get(subscription.reference).send().await;
 
             let Ok(response) = result else {
                 return None
             };
             
-            response.text().await.ok()
+            let Ok(text) = response.text().await else {
+                return None
+            };
+
+            text.parse::<icalendar::Calendar>().ok()
         })());
     }
 
-    let results = requests.join_all().await;
-    let icals = results.iter().filter_map(|ical| ical.to_owned());
-
-    let calendars: Vec<icalendar::Calendar> = icals.map(|ical| ical.parse::<icalendar::Calendar>()).filter_map(|calendar| calendar.ok()).collect();
+    let calendars = requests.join_all().await;
 
     let mut merged = icalendar::Calendar::new();
 
-    for calendar in calendars {
-        merged.extend(calendar.components);
+    for maybe_calendar in calendars {
+        if let Some(calendar) = maybe_calendar {
+            merged.extend(calendar.components);
+        }
     }
 
     Ok(merged.to_string())
 }
+
+#[cfg(feature = "ssr")]
+async fn list_dav_calendars(client: &CalDavClient) -> anyhow::Result<Vec<fast_dav_rs::CalendarInfo>, anyhow::Error> {
+    let Some(principal) = client.discover_current_user_principal().await? else {
+        return Err(anyhow::anyhow!("Incompatible: CalDav server does not indicate principal"))
+    };
+
+    let home_sets = client.discover_calendar_home_set(&principal).await?;
+
+    let mut calendars = vec![];
+
+    for home_set in home_sets {
+        calendars.extend(client.list_calendars(&home_set).await?);
+    }
+
+    Ok(calendars)
+}
+
+fn get_colored_components(color: Option<&str>, calendar: icalendar::Calendar) -> Vec<icalendar::CalendarComponent> {   
+    let Some(color) = calendar.property_value("COLOR").or_else(|| color) else {
+        return calendar.components
+    };
+
+    return calendar.components.iter().map(ToOwned::to_owned).map(|component| {
+        match component {
+            icalendar::CalendarComponent::Event(mut event) => {
+                if event.property_value("COLOR").is_none() {
+                    event.add_property("COLOR", color);
+                }
+
+                icalendar::CalendarComponent::Event(event)
+            },
+            icalendar::CalendarComponent::Todo(mut todo) => {
+                if todo.property_value("COLOR").is_none() {
+                    todo.add_property("COLOR", color);
+                }
+
+                icalendar::CalendarComponent::Todo(todo)
+            },
+            icalendar::CalendarComponent::Venue(mut venue) => {
+                if venue.property_value("COLOR").is_none() {
+                    venue.add_property("COLOR", color);
+                }
+
+                icalendar::CalendarComponent::Venue(venue)
+            },
+            other => other
+        }
+    }).collect()
+}
+
+#[cfg(feature = "ssr")]
+async fn get_dav_calendar(client: fast_dav_rs::CalDavClient, reference: &str) -> Option<icalendar::Calendar> {
+    let all_calendars = list_dav_calendars(&client).await.unwrap_or_else(|_| vec![]);
+
+    let color = all_calendars
+        .iter()
+        .filter(|calendar| calendar.href == reference && calendar.color.is_some())
+        .next()
+        .and_then(|calendar| calendar.color.clone());
+    
+    let Ok(result) = client.calendar_query_timerange(reference, "VEVENT", None, None, true).await else {
+        return None
+    };
+    
+    let mut calendar = icalendar::Calendar::new();
+
+    for calendar_object in result {
+        let Some(calendar_data) = calendar_object.calendar_data else {
+            continue
+        };
+
+        let Ok(parsed) = calendar_data.parse::<icalendar::Calendar>() else {
+            continue
+        };
+
+        calendar.extend(get_colored_components(color.as_deref(), parsed))
+    }
+
+    Some(calendar)
+}

src/main.rs

···
     use leptos_axum::{generate_route_list, LeptosRoutes};
     use calpoll::app::*;
     use sqlx::Connection;
+
+    rustls::crypto::ring::default_provider().install_default().expect("Failed to set default crypto provider for rustls..."); // Needed for fast-dav-rs since as it doesn't properly enable features...
     
     let connection =
         PgConnection::connect(
             env::var("DATABASE_URL")
                 .expect("Please ensure you set your database URL in the $DATABASE_URL environment variable")
-                .as_str()).await.unwrap();
+                .as_str()).await.expect("Failed to connect to database defined in $DATABASE_URL");
 
     STATE.set(State {
         sqlx_connection: Mutex::new(connection),
         reqwest_client: reqwest::Client::new(),
-    }).unwrap();
+    }).expect("Consistency issue: failed to set STATE - was it already set?");
 
     let conf = get_configuration(None).unwrap();
     let addr = conf.leptos_options.site_addr;
···
     let listener = tokio::net::TcpListener::bind(&addr).await.unwrap();
     axum::serve(listener, app.into_make_service())
         .await
-        .unwrap();
+        .expect("Failed to start axum server");
 }

test-data/merge-holidays-moon-phases.sql

···
 
 INSERT INTO calendars ("id", "user") VALUES ('32da8949-b21c-469d-a2bc-f5763af186c6', '11cd80d6-cf3d-4d93-9d47-4a383eaf1a10');
 
-INSERT INTO subscriptions ("id", "url") VALUES ('797de795-0ae5-443c-91d1-1d68f9d44889', 'https://calendar.google.com/calendar/ical/en.uk%23holiday%40group.v.calendar.google.com/public/basic.ics');
-INSERT INTO subscriptions ("id", "url") VALUES ('53d15eed-9db4-40ac-a5b1-b6df114847b2', 'https://calendar.google.com/calendar/ical/ht3jlfaac5lfd6263ulfh4tql8%40group.calendar.google.com/public/basic.ics');
+INSERT INTO subscriptions ("id", "reference") VALUES ('797de795-0ae5-443c-91d1-1d68f9d44889', 'https://calendar.google.com/calendar/ical/en.uk%23holiday%40group.v.calendar.google.com/public/basic.ics');
+INSERT INTO subscriptions ("id", "reference") VALUES ('53d15eed-9db4-40ac-a5b1-b6df114847b2', 'https://calendar.google.com/calendar/ical/ht3jlfaac5lfd6263ulfh4tql8%40group.calendar.google.com/public/basic.ics');
 
 INSERT INTO calendars_subscriptions ("calendars_id", "subscriptions_id") VALUES ('32da8949-b21c-469d-a2bc-f5763af186c6', '797de795-0ae5-443c-91d1-1d68f9d44889');
 INSERT INTO calendars_subscriptions ("calendars_id", "subscriptions_id") VALUES ('32da8949-b21c-469d-a2bc-f5763af186c6', '53d15eed-9db4-40ac-a5b1-b6df114847b2');