New endpoints for dcrweb statistics. (#184)

"price" endpoint serves USD prices for bitcoin and decred as reported by
dcrdata.

"webinfo" collects data from dcrdata and caches it, serves to JavaScript
running on the homepage of decred.org.

Both endpoints have a "last updated" field so clients can make their own
decisions on handling stale data.

Author: jholdstock

LICENSE

@@ -1,6 +1,6 @@
 ISC License
 
-Copyright (c) 2017-2023 The Decred developers
+Copyright (c) 2017-2024 The Decred developers
 
 Permission to use, copy, modify, and distribute this software for any
 purpose with or without fee is hereby granted, provided that the above

docs/api.md

@@ -32,3 +32,37 @@ Example: <https://api.decred.org/?c=vsp>
     },
 }
 ```
+
+## Web Info
+
+Collects data from dcrdata and caches it, serves to JavaScript running on the
+homepage of <https://decred.org>.
+
+Example: <https://api.decred.org/?c=webinfo>
+
+```json
+{
+    "circulatingsupply": 15804577.17784509,
+    "ultimatesupply": 20999999.9839432,
+    "stakedsupply": 9855286.05084056,
+    "blockreward": 8.061013,
+    "treasury": 822237.44313611,
+    "ticketprice": 268.19271648,
+    "height": 837324,
+    "lastupdated": 1706092430
+}
+```
+
+## Price Info
+
+Returns the current USD price of Bitcoin and Decred as reported by dcrdata.
+
+Example: <https://api.decred.org/?c=price>
+
+```json
+{
+    "bitcoin_usd": 40119.53495,
+    "decred_usd": 14.1665886541639,
+    "lastupdated": 1706092430
+}
+```

go.mod

@@ -2,6 +2,60 @@ module github.com/decred/dcrwebapi
 
 go 1.18
 
-require github.com/gorilla/handlers v1.5.1
+require (
+	github.com/decred/dcrd/dcrutil/v4 v4.0.0
+	github.com/decred/dcrdata/exchanges/v3 v3.1.0
+	github.com/decred/dcrdata/v6 v6.0.0
+	github.com/gorilla/handlers v1.5.1
+)
 
-require github.com/felixge/httpsnoop v1.0.3 // indirect
+require (
+	decred.org/dcrdex v0.4.3 // indirect
+	decred.org/dcrwallet v1.7.0 // indirect
+	github.com/agl/ed25519 v0.0.0-20170116200512-5312a6153412 // indirect
+	github.com/carterjones/go-cloudflare-scraper v0.1.2 // indirect
+	github.com/carterjones/signalr v0.3.5 // indirect
+	github.com/dchest/siphash v1.2.2 // indirect
+	github.com/decred/base58 v1.0.3 // indirect
+	github.com/decred/dcrd/blockchain/stake/v3 v3.0.0 // indirect
+	github.com/decred/dcrd/blockchain/standalone/v2 v2.1.0 // indirect
+	github.com/decred/dcrd/certgen v1.1.1 // indirect
+	github.com/decred/dcrd/chaincfg/chainhash v1.0.3 // indirect
+	github.com/decred/dcrd/chaincfg/v3 v3.1.1 // indirect
+	github.com/decred/dcrd/crypto/blake256 v1.0.1-0.20200921185235-6d75c7ec1199 // indirect
+	github.com/decred/dcrd/crypto/ripemd160 v1.0.1 // indirect
+	github.com/decred/dcrd/database/v2 v2.0.2 // indirect
+	github.com/decred/dcrd/dcrec v1.0.1-0.20200921185235-6d75c7ec1199 // indirect
+	github.com/decred/dcrd/dcrec/edwards/v2 v2.0.2 // indirect
+	github.com/decred/dcrd/dcrec/secp256k1/v3 v3.0.0 // indirect
+	github.com/decred/dcrd/dcrec/secp256k1/v4 v4.0.1 // indirect
+	github.com/decred/dcrd/dcrjson/v3 v3.1.0 // indirect
+	github.com/decred/dcrd/dcrutil/v3 v3.0.0 // indirect
+	github.com/decred/dcrd/hdkeychain/v3 v3.1.0 // indirect
+	github.com/decred/dcrd/rpc/jsonrpc/types/v2 v2.3.0 // indirect
+	github.com/decred/dcrd/txscript/v3 v3.0.0 // indirect
+	github.com/decred/dcrd/txscript/v4 v4.0.0 // indirect
+	github.com/decred/dcrd/wire v1.5.0 // indirect
+	github.com/decred/go-socks v1.1.0 // indirect
+	github.com/decred/slog v1.2.0 // indirect
+	github.com/felixge/httpsnoop v1.0.3 // indirect
+	github.com/go-chi/chi/v5 v5.0.4 // indirect
+	github.com/golang/protobuf v1.4.3 // indirect
+	github.com/golang/snappy v0.0.4 // indirect
+	github.com/gorilla/websocket v1.4.2 // indirect
+	github.com/lib/pq v1.10.3 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/robertkrimen/otto v0.0.0-20180617131154-15f95af6e78d // indirect
+	github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7 // indirect
+	go.etcd.io/bbolt v1.3.7-0.20220130032806-d5db64bdbfde // indirect
+	golang.org/x/crypto v0.0.0-20210711020723-a769d52b0f97 // indirect
+	golang.org/x/net v0.0.0-20210903162142-ad29c8ab022f // indirect
+	golang.org/x/sys v0.0.0-20210902050250-f475640dd07b // indirect
+	golang.org/x/text v0.3.6 // indirect
+	golang.org/x/time v0.0.0-20210220033141-f8bda1e9f3ba // indirect
+	google.golang.org/genproto v0.0.0-20201022181438-0ff5f38871d5 // indirect
+	google.golang.org/grpc v1.36.1 // indirect
+	google.golang.org/protobuf v1.25.0 // indirect
+	gopkg.in/ini.v1 v1.55.0 // indirect
+	gopkg.in/sourcemap.v1 v1.0.5 // indirect
+)