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import gleam/http/response.{Response}
import gleam/http/request.{Request}
import gleam/http.{Get}
import gleam/bit_builder.{BitBuilder}
import gleam/erlang/process
import gleam/io
import gleam/string
import gleam/list
import gleam/map.{Map}
import gleam/result.{lazy_unwrap}
import gleam/uri
import gleam/hackney
import mist
fn the_lookup(
query: String,
stations: Map(String, String),
ds100s: Map(String, String),
) -> String {
map.get(ds100s, query)
|> lazy_unwrap(fn() {
io.println(query)
map.get(stations, query)
|> lazy_unwrap(fn() { "unknown" })
})
}
fn lookup_station(
request: Request(t),
stations: Map(String, String),
ds100s: Map(String, String),
baseurl: String,
) -> Response(BitBuilder) {
let #(code, text) = case request {
Request(method: Get, path: "/help", ..) -> #(
200,
"ds100 → Name: " <> baseurl <> "/FF\n" <> "Name → ds100: " <> baseurl <> "/Frankfurt Hbf",
)
Request(method: Get, path: "/" <> path, ..) -> #(
200,
the_lookup(string.replace(path, each: "%20", with: " "), stations, ds100s),
)
_ -> #(404, "intended usage is e.g. curl " <> baseurl <> "/FF")
}
let body = bit_builder.from_string(text)
response.new(code)
|> response.prepend_header(
"x-data-source",
"https://data.deutschebahn.com/dataset/data-betriebsstellen.html",
)
|> response.set_body(body)
}
fn fetch_data() -> Result(String, hackney.Error) {
let assert Ok(uri) =
uri.parse(
"https://download-data.deutschebahn.com/static/datasets/betriebsstellen/DBNetz-Betriebsstellenverzeichnis-Stand2021-10.csv",
)
let assert Ok(request) = request.from_uri(uri)
let assert Ok(response) = hackney.send(request)
Ok(response.body)
}
fn read_csv() -> List(#(String, String)) {
// let assert Ok(contents) = file.read(path)
let assert Ok(contents) = fetch_data()
contents
// the file doesn't use quotes, so this is fine
|> string.split(on: "\n")
|> list.map(fn(a) { string.split(a, on: ";") })
|> list.filter_map(fn(fields) {
case fields {
[_, ds100, name, ..] -> Ok(#(name, ds100))
_ -> Error(fields)
}
})
}
pub fn main() {
let baseurl = "https://bahnhof.name"
let stations = read_csv()
let stationmap =
stations
|> map.from_list
let ds100map =
stations
|> list.map(fn(a) { #(a.1, a.0) })
|> map.from_list
let assert Ok(_) = mist.run_service(
1234,
fn(req) { lookup_station(req, stationmap, ds100map, baseurl) },
max_body_limit: 100,
)
process.sleep_forever()
}
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