feat: add ical calendar merging

A key function of calpoll is taking multiple .ics calendars and merging
them together. This adds basic ical merging as follows:

- "Calendars" are in a database
- Calendars have multiple "subscriptions" (ical subscription URLs)
- When getting events from a calendar, we fetch all subscriptions, parse
them and add everything to one big ical file
- We expose this over http so this can itself be used as an ical
subscription URL

The reason we do it like this rather than, say, having an endpoint to
/merge/ calendars and be done with it is we want this to be an
application which you can share URLs out of even if you don't want to
make the subscription URLs of each underlying calendar public (e.g.
Google Calendar private .ics subscription links). We would also like the
ability to add support for more calendar sources in the future -
particularly, say, I need support for WebDav calendars for Stalwart.

---

You can test this change by using the merge-holidays-moon-phases.sql
queries in test-data/ to set up a test calendar like so:

$ cat test-data/merge-holidays-moon-phases.sql | psql $DATABASE_URL
$ curl http://127.0.0.1:3000/calendar/32da8949-b21c-469d-a2bc-f5763af186c6
BEGIN:VCALENDAR
VERSION:2.0
PRODID:ICALENDAR-RS
CALSCALE:GREGORIAN
BEGIN:VEVENT
CLASS:PUBLIC
CREATED:20240522T091304Z
DESCRIPTION:Public holiday
[...]

$ curl http://127.0.0.1:3000/calendar/00069420-74d2-4ba8-85d6-4fc679810c02
BEGIN:VCALENDAR
VERSION:2.0
PRODID:ICALENDAR-RS
CALSCALE:GREGORIAN
END:VCALENDAR

$ curl http://127.0.0.1:3000/calendar/non-uuid
Invalid URL: Cannot parse `id` with value `non-uuid`: UUID parsing
failed: invalid character: expected an optional prefix of `urn:uuid:`
followed by [0-9a-fA-F-], found `n` at 1

---

For these tests to work, you'll need to have $DATABASE_URL set to your
database, and you'll have to be running the code. The easiest way to do
that is with devenv and the nilla shell provided here...

$ devenv up
[...wait for TUI showing postgres running...]

[...in a separate terminal...]
$ nilla shell
nilla$ sqlx database reset
nilla$ cat test-data/merge-holidays-moon-phases.sql | psql $DATABASE_URL
nilla$ cargo leptos watch

.gitignore

···
 .sass-cache
 /debug
 /target
+/test-data/private-*

Cargo.lock

···
 checksum = "683d7910e743518b0e34f1186f92494becacb047c7b6bf616c96772180fef923"
 
 [[package]]
+name = "android_system_properties"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "819e7219dbd41043ac279b19830f2efc897156490d7fd6ea916720117ee66311"
+dependencies = [
+ "libc",
+]
+
+[[package]]
 name = "any_spawner"
 version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 name = "calpoll"
 version = "0.1.0"
 dependencies = [
+ "anyhow",
  "axum",
  "console_error_panic_hook",
+ "icalendar",
  "leptos",
  "leptos_axum",
  "leptos_meta",
  "leptos_router",
+ "reqwest",
  "sqlx",
  "tokio",
+ "uuid",
  "wasm-bindgen",
 ]
 
···
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
 [[package]]
+name = "cfg_aliases"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"
+
+[[package]]
+name = "chrono"
+version = "0.4.42"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "145052bdd345b87320e369255277e3fb5152762ad123a901ef5c262dd38fe8d2"
+dependencies = [
+ "iana-time-zone",
+ "js-sys",
+ "num-traits",
+ "wasm-bindgen",
+ "windows-link 0.2.1",
+]
+
+[[package]]
+name = "chrono-tz"
+version = "0.10.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a6139a8597ed92cf816dfb33f5dd6cf0bb93a6adc938f11039f371bc5bcd26c3"
+dependencies = [
+ "chrono",
+ "phf",
+]
+
+[[package]]
 name = "codee"
 version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 ]
 
 [[package]]
+name = "deranged"
+version = "0.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a41953f86f8a05768a6cda24def994fd2f424b04ec5c719cf89989779f199071"
+dependencies = [
+ "powerfmt",
+]
+
+[[package]]
 name = "derive-where"
 version = "1.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 checksum = "335ff9f135e4384c8150d6f27c6daed433577f86b4750418338c01a1a2528592"
 dependencies = [
  "cfg-if",
+ "js-sys",
  "libc",
  "wasi",
+ "wasm-bindgen",
 ]
 
 [[package]]
···
 version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "17e2ac29387b1aa07a1e448f7bb4f35b500787971e965b02842b900afa5c8f6f"
+
+[[package]]
+name = "h2"
+version = "0.4.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3c0b69cfcb4e1b9f1bf2f53f95f766e4661169728ec61cd3fe5a0166f2d1386"
+dependencies = [
+ "atomic-waker",
+ "bytes",
+ "fnv",
+ "futures-core",
+ "futures-sink",
+ "http",
+ "indexmap",
+ "slab",
+ "tokio",
+ "tokio-util",
+ "tracing",
+]
 
 [[package]]
 name = "hashbrown"
···
  "bytes",
  "futures-channel",
  "futures-core",
+ "h2",
  "http",
  "http-body",
  "httparse",
···
  "pin-utils",
  "smallvec",
  "tokio",
+ "want",
+]
+
+[[package]]
+name = "hyper-rustls"
+version = "0.27.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3c93eb611681b207e1fe55d5a71ecf91572ec8a6705cdb6857f7d8d5242cf58"
+dependencies = [
+ "http",
+ "hyper",
+ "hyper-util",
+ "rustls",
+ "rustls-pki-types",
+ "tokio",
+ "tokio-rustls",
+ "tower-service",
+ "webpki-roots 1.0.3",
+]
+
+[[package]]
+name = "hyper-tls"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "70206fc6890eaca9fde8a0bf71caa2ddfc9fe045ac9e5c70df101a7dbde866e0"
+dependencies = [
+ "bytes",
+ "http-body-util",
+ "hyper",
+ "hyper-util",
+ "native-tls",
+ "tokio",
+ "tokio-native-tls",
+ "tower-service",
 ]
 
 [[package]]
···
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3c6995591a8f1380fcb4ba966a252a4b29188d51d2b89e3a252f5305be65aea8"
 dependencies = [
+ "base64",
  "bytes",
+ "futures-channel",
  "futures-core",
+ "futures-util",
  "http",
  "http-body",
  "hyper",
+ "ipnet",
+ "libc",
+ "percent-encoding",
  "pin-project-lite",
+ "socket2",
+ "system-configuration",
  "tokio",
  "tower-service",
+ "tracing",
+ "windows-registry",
+]
+
+[[package]]
+name = "iana-time-zone"
+version = "0.1.64"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "33e57f83510bb73707521ebaffa789ec8caf86f9657cad665b092b581d40e9fb"
+dependencies = [
+ "android_system_properties",
+ "core-foundation-sys",
+ "iana-time-zone-haiku",
+ "js-sys",
+ "log",
+ "wasm-bindgen",
+ "windows-core",
+]
+
+[[package]]
+name = "iana-time-zone-haiku"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f31827a206f56af32e590ba56d5d2d085f558508192593743f16b2306495269f"
+dependencies = [
+ "cc",
+]
+
+[[package]]
+name = "icalendar"
+version = "0.17.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f25bc68d1c3113be52919708c870cabe55ba0646b9dade87913fe565aa956a3b"
+dependencies = [
+ "chrono",
+ "chrono-tz",
+ "iso8601",
+ "nom",
+ "nom-language",
+ "serde",
+ "time",
+ "uuid",
 ]
 
 [[package]]
···
 ]
 
 [[package]]
+name = "ipnet"
+version = "2.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "469fb0b9cefa57e3ef31275ee7cacb78f2fdca44e4765491884a2b119d4eb130"
+
+[[package]]
+name = "iri-string"
+version = "0.7.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dbc5ebe9c3a1a7a5127f920a418f7585e9e758e911d0466ed004f393b0e380b2"
+dependencies = [
+ "memchr",
+ "serde",
+]
+
+[[package]]
+name = "iso8601"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e1082f0c48f143442a1ac6122f67e360ceee130b967af4d50996e5154a45df46"
+dependencies = [
+ "nom",
+]
+
+[[package]]
 name = "itertools"
 version = "0.14.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 checksum = "34080505efa8e45a4b816c349525ebe327ceaa8559756f0356cba97ef3bf7432"
 
 [[package]]
+name = "lru-slab"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "112b39cec0b298b6c1999fee3e31427f74f676e4cb9879ed1a121b43661a4154"
+
+[[package]]
 name = "manyhow"
 version = "0.11.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 checksum = "60993920e071b0c9b66f14e2b32740a4e27ffc82854dcd72035887f336a09a28"
 
 [[package]]
+name = "nom"
+version = "8.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df9761775871bdef83bee530e60050f7e54b1105350d6884eb0fb4f46c2f9405"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "nom-language"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2de2bc5b451bfedaef92c90b8939a8fff5770bdcc1fafd6239d086aab8fa6b29"
+dependencies = [
+ "nom",
+]
+
+[[package]]
 name = "num-bigint-dig"
 version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
  "smallvec",
  "zeroize",
 ]
+
+[[package]]
+name = "num-conv"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "51d515d32fb182ee37cda2ccdcb92950d6a3c2893aa280e540671c2cd0f3b1d9"
 
 [[package]]
 name = "num-integer"
···
  "libc",
  "redox_syscall",
  "smallvec",
- "windows-link",
+ "windows-link 0.2.1",
 ]
 
 [[package]]
···
 version = "2.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9b4f627cb1b25917193a259e49bdad08f671f8d9708acfd5fe0a8c1455d87220"
+
+[[package]]
+name = "phf"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "913273894cec178f401a31ec4b656318d95473527be05c0752cc41cdc32be8b7"
+dependencies = [
+ "phf_shared",
+]
+
+[[package]]
+name = "phf_shared"
+version = "0.12.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06005508882fb681fd97892ecff4b7fd0fee13ef1aa569f8695dae7ab9099981"
+dependencies = [
+ "siphasher",
+]
 
 [[package]]
 name = "pin-project"
···
 ]
 
 [[package]]
+name = "powerfmt"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "439ee305def115ba05938db6eb1644ff94165c5ab5e9420d1c1bcedbba909391"
+
+[[package]]
 name = "ppv-lite86"
 version = "0.2.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 ]
 
 [[package]]
+name = "quinn"
+version = "0.11.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9e20a958963c291dc322d98411f541009df2ced7b5a4f2bd52337638cfccf20"
+dependencies = [
+ "bytes",
+ "cfg_aliases",
+ "pin-project-lite",
+ "quinn-proto",
+ "quinn-udp",
+ "rustc-hash",
+ "rustls",
+ "socket2",
+ "thiserror 2.0.17",
+ "tokio",
+ "tracing",
+ "web-time",
+]
+
+[[package]]
+name = "quinn-proto"
+version = "0.11.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f1906b49b0c3bc04b5fe5d86a77925ae6524a19b816ae38ce1e426255f1d8a31"
+dependencies = [
+ "bytes",
+ "getrandom 0.3.4",
+ "lru-slab",
+ "rand 0.9.2",
+ "ring",
+ "rustc-hash",
+ "rustls",
+ "rustls-pki-types",
+ "slab",
+ "thiserror 2.0.17",
+ "tinyvec",
+ "tracing",
+ "web-time",
+]
+
+[[package]]
+name = "quinn-udp"
+version = "0.5.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "addec6a0dcad8a8d96a771f815f0eaf55f9d1805756410b39f5fa81332574cbd"
+dependencies = [
+ "cfg_aliases",
+ "libc",
+ "once_cell",
+ "socket2",
+ "tracing",
+ "windows-sys 0.60.2",
+]
+
+[[package]]
 name = "quote"
 version = "1.0.41"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 checksum = "7a2d987857b319362043e95f5353c0535c1f58eec5336fdfcf626430af7def58"
 
 [[package]]
+name = "reqwest"
+version = "0.12.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9d0946410b9f7b082a427e4ef5c8ff541a88b357bc6c637c40db3a68ac70a36f"
+dependencies = [
+ "base64",
+ "bytes",
+ "encoding_rs",
+ "futures-core",
+ "h2",
+ "http",
+ "http-body",
+ "http-body-util",
+ "hyper",
+ "hyper-rustls",
+ "hyper-tls",
+ "hyper-util",
+ "js-sys",
+ "log",
+ "mime",
+ "native-tls",
+ "percent-encoding",
+ "pin-project-lite",
+ "quinn",
+ "rustls",
+ "rustls-pki-types",
+ "serde",
+ "serde_json",
+ "serde_urlencoded",
+ "sync_wrapper",
+ "tokio",
+ "tokio-native-tls",
+ "tokio-rustls",
+ "tower",
+ "tower-http",
+ "tower-service",
+ "url",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "web-sys",
+ "webpki-roots 1.0.3",
+]
+
+[[package]]
+name = "ring"
+version = "0.17.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a4689e6c2294d81e88dc6261c768b63bc4fcdb852be6d1352498b114f61383b7"
+dependencies = [
+ "cc",
+ "cfg-if",
+ "getrandom 0.2.16",
+ "libc",
+ "untrusted",
+ "windows-sys 0.52.0",
+]
+
+[[package]]
 name = "rsa"
 version = "0.9.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 ]
 
 [[package]]
+name = "rustls"
+version = "0.23.34"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a9586e9ee2b4f8fab52a0048ca7334d7024eef48e2cb9407e3497bb7cab7fa7"
+dependencies = [
+ "once_cell",
+ "ring",
+ "rustls-pki-types",
+ "rustls-webpki",
+ "subtle",
+ "zeroize",
+]
+
+[[package]]
+name = "rustls-pki-types"
+version = "1.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "229a4a4c221013e7e1f1a043678c5cc39fe5171437c88fb47151a21e6f5b5c79"
+dependencies = [
+ "web-time",
+ "zeroize",
+]
+
+[[package]]
+name = "rustls-webpki"
+version = "0.103.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e10b3f4191e8a80e6b43eebabfac91e5dcecebb27a71f04e820c47ec41d314bf"
+dependencies = [
+ "ring",
+ "rustls-pki-types",
+ "untrusted",
+]
+
+[[package]]
 name = "rustversion"
 version = "1.0.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
  "digest",
  "rand_core 0.6.4",
 ]
+
+[[package]]
+name = "siphasher"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "56199f7ddabf13fe5074ce809e7d3f42b42ae711800501b5b16ea82ad029c39d"
 
 [[package]]
 name = "slab"
···
  "native-tls",
  "once_cell",
  "percent-encoding",
+ "rustls",
  "serde",
  "serde_json",
  "sha2",
···
  "tracing",
  "url",
  "uuid",
+ "webpki-roots 0.26.11",
 ]
 
 [[package]]
···
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0bf256ce5efdfa370213c1dabab5935a12e49f2c58d15e9eac2870d3b4f27263"
+dependencies = [
+ "futures-core",
+]
 
 [[package]]
 name = "synstructure"
···
 ]
 
 [[package]]
+name = "system-configuration"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3c879d448e9d986b661742763247d3693ed13609438cf3d006f51f5368a5ba6b"
+dependencies = [
+ "bitflags",
+ "core-foundation",
+ "system-configuration-sys",
+]
+
+[[package]]
+name = "system-configuration-sys"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e1d1b10ced5ca923a1fcb8d03e96b8d3268065d724548c0211415ff6ac6bac4"
+dependencies = [
+ "core-foundation-sys",
+ "libc",
+]
+
+[[package]]
 name = "tachys"
 version = "0.2.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 ]
 
 [[package]]
+name = "time"
+version = "0.3.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "91e7d9e3bb61134e77bde20dd4825b97c010155709965fedf0f49bb138e52a9d"
+dependencies = [
+ "deranged",
+ "num-conv",
+ "powerfmt",
+ "serde",
+ "time-core",
+]
+
+[[package]]
+name = "time-core"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "40868e7c1d2f0b8d73e4a8c7f0ff63af4f6d19be117e90bd73eb1d62cf831c6b"
+
+[[package]]
 name = "tinystr"
 version = "0.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 ]
 
 [[package]]
+name = "tokio-native-tls"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbae76ab933c85776efabc971569dd6119c580d8f5d448769dec1764bf796ef2"
+dependencies = [
+ "native-tls",
+ "tokio",
+]
+
+[[package]]
+name = "tokio-rustls"
+version = "0.26.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1729aa945f29d91ba541258c8df89027d5792d85a8841fb65e8bf0f4ede4ef61"
+dependencies = [
+ "rustls",
+ "tokio",
+]
+
+[[package]]
 name = "tokio-stream"
 version = "0.1.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
  "http-body-util",
  "http-range-header",
  "httpdate",
+ "iri-string",
  "mime",
  "mime_guess",
  "percent-encoding",
  "pin-project-lite",
  "tokio",
  "tokio-util",
+ "tower",
  "tower-layer",
  "tower-service",
  "tracing",
···
 dependencies = [
  "once_cell",
 ]
+
+[[package]]
+name = "try-lock"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e421abadd41a4225275504ea4d6566923418b7f05506fbc9c0fe86ba7396114b"
 
 [[package]]
 name = "tungstenite"
···
 checksum = "ebc1c04c71510c7f702b52b7c350734c9ff1295c464a03335b00bb84fc54f853"
 
 [[package]]
+name = "untrusted"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ecb6da28b8a351d773b68d5825ac39017e680750f980f3a1a85cd8dd28a47c1"
+
+[[package]]
 name = "url"
 version = "2.5.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 dependencies = [
  "getrandom 0.3.4",
  "js-sys",
+ "serde",
  "wasm-bindgen",
 ]
 
···
 dependencies = [
  "same-file",
  "winapi-util",
+]
+
+[[package]]
+name = "want"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bfa7760aed19e106de2c7c0b581b509f2f25d3dacaf737cb82ac61bc6d760b0e"
+dependencies = [
+ "try-lock",
 ]
 
 [[package]]
···
 ]
 
 [[package]]
+name = "web-time"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a6580f308b1fad9207618087a65c04e7a10bc77e02c8e84e9b00dd4b12fa0bb"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "webpki-roots"
+version = "0.26.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "521bc38abb08001b01866da9f51eb7c5d647a19260e00054a8c7fd5f9e57f7a9"
+dependencies = [
+ "webpki-roots 1.0.3",
+]
+
+[[package]]
+name = "webpki-roots"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32b130c0d2d49f8b6889abc456e795e82525204f27c42cf767cf0d7734e089b8"
+dependencies = [
+ "rustls-pki-types",
+]
+
+[[package]]
 name = "whoami"
 version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 dependencies = [
  "windows-sys 0.61.2",
 ]
+
+[[package]]
+name = "windows-core"
+version = "0.62.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b8e83a14d34d0623b51dce9581199302a221863196a1dde71a7663a4c2be9deb"
+dependencies = [
+ "windows-implement",
+ "windows-interface",
+ "windows-link 0.2.1",
+ "windows-result 0.4.1",
+ "windows-strings 0.5.1",
+]
+
+[[package]]
+name = "windows-implement"
+version = "0.60.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "053e2e040ab57b9dc951b72c264860db7eb3b0200ba345b4e4c3b14f67855ddf"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "windows-interface"
+version = "0.59.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f316c4a2570ba26bbec722032c4099d8c8bc095efccdc15688708623367e358"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "windows-link"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e6ad25900d524eaabdbbb96d20b4311e1e7ae1699af4fb28c17ae66c80d798a"
 
 [[package]]
 name = "windows-link"
···
 checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
 
 [[package]]
+name = "windows-registry"
+version = "0.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b8a9ed28765efc97bbc954883f4e6796c33a06546ebafacbabee9696967499e"
+dependencies = [
+ "windows-link 0.1.3",
+ "windows-result 0.3.4",
+ "windows-strings 0.4.2",
+]
+
+[[package]]
+name = "windows-result"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "56f42bd332cc6c8eac5af113fc0c1fd6a8fd2aa08a0119358686e5160d0586c6"
+dependencies = [
+ "windows-link 0.1.3",
+]
+
+[[package]]
+name = "windows-result"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7781fa89eaf60850ac3d2da7af8e5242a5ea78d1a11c49bf2910bb5a73853eb5"
+dependencies = [
+ "windows-link 0.2.1",
+]
+
+[[package]]
+name = "windows-strings"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "56e6c93f3a0c3b36176cb1327a4958a0353d5d166c2a35cb268ace15e91d3b57"
+dependencies = [
+ "windows-link 0.1.3",
+]
+
+[[package]]
+name = "windows-strings"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7837d08f69c77cf6b07689544538e017c1bfcf57e34b4c0ff58e6c2cd3b37091"
+dependencies = [
+ "windows-link 0.2.1",
+]
+
+[[package]]
 name = "windows-sys"
 version = "0.48.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
···
 
 [[package]]
 name = "windows-sys"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "282be5f36a8ce781fad8c8ae18fa3f9beff57ec1b52cb3de0789201425d9a33d"
+dependencies = [
+ "windows-targets 0.52.6",
+]
+
+[[package]]
+name = "windows-sys"
 version = "0.60.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f2f500e4d28234f72040990ec9d39e3a6b950f9f22d3dba18416c35882612bcb"
···
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
 dependencies = [
- "windows-link",
+ "windows-link 0.2.1",
 ]
 
 [[package]]
···
 
 [[package]]
 name = "windows-targets"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b724f72796e036ab90c1021d4780d4d3d648aca59e491e6b98e725b84e99973"
+dependencies = [
+ "windows_aarch64_gnullvm 0.52.6",
+ "windows_aarch64_msvc 0.52.6",
+ "windows_i686_gnu 0.52.6",
+ "windows_i686_gnullvm 0.52.6",
+ "windows_i686_msvc 0.52.6",
+ "windows_x86_64_gnu 0.52.6",
+ "windows_x86_64_gnullvm 0.52.6",
+ "windows_x86_64_msvc 0.52.6",
+]
+
+[[package]]
+name = "windows-targets"
 version = "0.53.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4945f9f551b88e0d65f3db0bc25c33b8acea4d9e41163edf90dcd0b19f9069f3"
 dependencies = [
- "windows-link",
+ "windows-link 0.2.1",
  "windows_aarch64_gnullvm 0.53.1",
  "windows_aarch64_msvc 0.53.1",
  "windows_i686_gnu 0.53.1",
- "windows_i686_gnullvm",
+ "windows_i686_gnullvm 0.53.1",
  "windows_i686_msvc 0.53.1",
  "windows_x86_64_gnu 0.53.1",
  "windows_x86_64_gnullvm 0.53.1",
···
 version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2b38e32f0abccf9987a4e3079dfb67dcd799fb61361e53e2882c3cbaf0d905d8"
+
+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32a4622180e7a0ec044bb555404c800bc9fd9ec262ec147edd5989ccd0c02cd3"
 
 [[package]]
 name = "windows_aarch64_gnullvm"
···
 
 [[package]]
 name = "windows_aarch64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09ec2a7bb152e2252b53fa7803150007879548bc709c039df7627cabbd05d469"
+
+[[package]]
+name = "windows_aarch64_msvc"
 version = "0.53.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b9d782e804c2f632e395708e99a94275910eb9100b2114651e04744e9b125006"
···
 
 [[package]]
 name = "windows_i686_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e9b5ad5ab802e97eb8e295ac6720e509ee4c243f69d781394014ebfe8bbfa0b"
+
+[[package]]
+name = "windows_i686_gnu"
 version = "0.53.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "960e6da069d81e09becb0ca57a65220ddff016ff2d6af6a223cf372a506593a3"
+
+[[package]]
+name = "windows_i686_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0eee52d38c090b3caa76c563b86c3a4bd71ef1a819287c19d586d7334ae8ed66"
 
 [[package]]
 name = "windows_i686_gnullvm"
···
 
 [[package]]
 name = "windows_i686_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"
+
+[[package]]
+name = "windows_i686_msvc"
 version = "0.53.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1e7ac75179f18232fe9c285163565a57ef8d3c89254a30685b57d83a38d326c2"
···
 
 [[package]]
 name = "windows_x86_64_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "147a5c80aabfbf0c7d901cb5895d1de30ef2907eb21fbbab29ca94c5b08b1a78"
+
+[[package]]
+name = "windows_x86_64_gnu"
 version = "0.53.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c3842cdd74a865a8066ab39c8a7a473c0778a3f29370b5fd6b4b9aa7df4a499"
···
 
 [[package]]
 name = "windows_x86_64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"
+
+[[package]]
+name = "windows_x86_64_gnullvm"
 version = "0.53.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0ffa179e2d07eee8ad8f57493436566c7cc30ac536a3379fdf008f47f6bb7ae1"
···
 version = "0.48.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ed94fce61571a4006852b7389a063ab983c02eb1bb37b47f8272ce92d06d9538"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
 
 [[package]]
 name = "windows_x86_64_msvc"

Cargo.toml

···
 leptos_meta = { version = "0.8.0" }
 tokio = { version = "1", features = ["rt-multi-thread"], optional = true }
 wasm-bindgen = { version = "=0.2.100", optional = true }
-sqlx = { version = "0.8.6", features = ["runtime-tokio", "tls-native-tls", "postgres", "uuid", "macros"] }
+sqlx = { version = "0.8.6", features = ["runtime-tokio", "tls-native-tls", "postgres", "uuid", "macros", "tls-rustls-ring-webpki"], optional = true }
+uuid = { version = "1.18.1", features = ["js", "serde", "v4"], optional = true }
+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 }
 
 [features]
 hydrate = [
···
 ]
 ssr = [
     "dep:axum",
-    "dep:tokio",
+    "dep:icalendar",
     "dep:leptos_axum",
+    "dep:reqwest",
+    "dep:sqlx",
+    "dep:tokio",
+    "dep:uuid",
     "leptos/ssr",
     "leptos_meta/ssr",
     "leptos_router/ssr",

migrations/20251026145212_add-calendars.sql

···
+CREATE TABLE "subscriptions" (
+  "id" uuid PRIMARY KEY,
+  "url" varchar NOT NULL
+);
+
+CREATE TABLE "calendars" (
+  "id" uuid PRIMARY KEY,
+  "user" uuid NOT NULL
+);
+
+CREATE TABLE "users" (
+  "id" uuid PRIMARY KEY
+);
+
+CREATE TABLE "calendars_subscriptions" (
+  "calendars_id" uuid,
+  "subscriptions_id" uuid,
+  PRIMARY KEY ("calendars_id", "subscriptions_id")
+);
+
+ALTER TABLE "calendars_subscriptions" ADD FOREIGN KEY ("calendars_id") REFERENCES "calendars" ("id");
+
+ALTER TABLE "calendars_subscriptions" ADD FOREIGN KEY ("subscriptions_id") REFERENCES "subscriptions" ("id");
+
+
+ALTER TABLE "calendars" ADD CONSTRAINT "user_calendars" FOREIGN KEY ("user") REFERENCES "users" ("id");

src/calendar.rs

···
+use std::ops::DerefMut;
+
 use axum::extract::Path;
+use leptos::prelude::ServerFnError;
+use leptos::server;
+use tokio::task::JoinSet;
+use uuid::Uuid;
+
+use crate::STATE;
 
-pub(crate) async fn route(Path(_path): Path<String>) -> String {
-    "hello world!".to_string()
+pub(crate) async fn route(
+    Path(id): Path<Uuid>
+) -> String {
+    events_by_calendar(id).await.unwrap()
+}
+
+#[server]
+async fn events_by_calendar(id: Uuid) -> anyhow::Result<String, ServerFnError> {
+    let state = STATE.get().unwrap();
+
+    println!("{:?}", id);
+
+    let subscription_urls = sqlx::query!(
+        "SELECT url 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",
+        id
+    ).fetch_all(state.sqlx_connection.lock().await.deref_mut()).await?;
+
+    println!("{:#?}", subscription_urls);
+
+    let mut requests = JoinSet::new();
+
+    for url in subscription_urls {
+        requests.spawn((async || {
+            let result = state.reqwest_client.get(url.url).send().await;
+
+            let Ok(response) = result else {
+                return None
+            };
+            
+            response.text().await.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 mut merged = icalendar::Calendar::new();
+
+    for calendar in calendars {
+        merged.extend(calendar.components);
+    }
+
+    Ok(merged.to_string())
 }

src/main.rs

···
+use std::sync::OnceLock;
+use sqlx::PgConnection;
+use tokio::sync::Mutex;
+
 mod calendar;
+
+#[cfg(feature = "ssr")]
+#[derive(Debug)]
+pub struct State {
+    sqlx_connection: Mutex<PgConnection>,
+    reqwest_client: reqwest::Client,
+}
+
+#[cfg(feature = "ssr")]
+static STATE: OnceLock<State> = OnceLock::new();
 
 #[cfg(feature = "ssr")]
 #[tokio::main]
 async fn main() {
+    use std::env;
+
     use axum::{routing::get, Router};
     use leptos::logging::log;
     use leptos::prelude::*;
     use leptos_axum::{generate_route_list, LeptosRoutes};
     use calpoll::app::*;
+    use sqlx::Connection;
+    
+    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();
+
+    STATE.set(State {
+        sqlx_connection: Mutex::new(connection),
+        reqwest_client: reqwest::Client::new(),
+    }).unwrap();
 
     let conf = get_configuration(None).unwrap();
     let addr = conf.leptos_options.site_addr;

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

···
+INSERT INTO users ("id") VALUES ('11cd80d6-cf3d-4d93-9d47-4a383eaf1a10');
+
+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 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');