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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/erlang/atom
import gleam/io
import gleam/int
import gleam/string
import gleam/bit_string
import gleam/list
import gleam/map.{Map}
import gleam/uri
import gleam/hackney
import mist
external type Index
external type Field
external fn index_new(atom.Atom) -> Index =
"Elixir.Haystack.Index" "new"
external fn index_ref(Index, Field) -> Index =
"Elixir.Haystack.Index" "ref"
external fn index_field(Index, Field) -> Index =
"Elixir.Haystack.Index" "field"
external fn field_term(String) -> Field =
"Elixir.Haystack.Index.Field" "term"
external fn field_new(String) -> Field =
"Elixir.Haystack.Index.Field" "new"
external fn index_add(Index, List(a)) -> Index =
"Elixir.Haystack.Index" "add"
external fn index_search(Index, String) -> List(Map(atom.Atom, String)) =
"Elixir.Haystack.Index" "search"
pub external fn inspect(a) -> a =
"Elixir.IO" "inspect"
external type Query
external type Clause
external type Expression
external fn query_new() -> Query =
"Elixir.Haystack.Query" "new"
external fn query_clause(Query, Clause) -> Query =
"Elixir.Haystack.Query" "clause"
external fn query_run(Query, Index) -> List(Map(atom.Atom, String)) =
"Elixir.Haystack.Query" "run"
external fn clause_new(atom.Atom) -> Clause =
"Elixir.Haystack.Query.Clause" "new"
external fn query_expressions(Clause, List(Expression)) -> Clause =
"Elixir.Haystack.Query.Clause" "expressions"
external fn query_expression_new(atom.Atom, List(#(atom.Atom, String))) -> Expression =
"Elixir.Haystack.Query.Expression" "new"
external fn tokenize(String) -> List(Map(atom.Atom, String)) =
"Elixir.Haystack.Tokenizer" "tokenize"
fn unpercent(encoded: String) -> String {
let #([head], chunks) =
encoded
|> string.split(on: "%")
|> list.split(at: 1)
let assert Ok(res) =
chunks
|> list.map(fn(str) {
case string.length(str) < 2 {
True -> bit_string.from_string(str)
False -> {
let assert Ok(codepoint) =
str
|> string.slice(at_index: 0, length: 2)
|> int.base_parse(16)
<<codepoint:8, string.drop_left(str, 2):utf8>>
}
}
})
|> list.prepend(bit_string.from_string(head))
|> bit_string.concat
|> bit_string.to_string
res
}
fn the_lookup(
query: String,
stations: Map(String, String),
ds100s: Map(String, String),
fuzzy: fn(String) -> List(String)
) -> #(Int, String) {
case map.get(ds100s, query) {
Ok(name) -> #(200, name)
_ -> {
io.println(query)
case map.get(stations, query) {
Ok(ds100) -> #(200, ds100)
_ -> {
let results = fuzzy(query)
|> list.filter_map(fn (res) { map.get(ds100s, string.uppercase(res)) })
case results {
// results -> {
// let names = results
// |> list.map (fn (res) {
// map.get(ds100s, string.uppercase(res))
// |> result.map(fn(a) { "/" <> a })
// |> result.unwrap("/")})
// #(200, string.join(names, "\n"))
// }
[res] -> #(302, res)
[res, ..] -> #(302, res)
_ -> #(404, "??")
}
}
}
}
}
}
fn lookup_station(
request: Request(t),
stations: Map(String, String),
ds100s: Map(String, String),
baseurl: String,
fuzzy: fn (String) -> List(String)
) -> Response(BitBuilder) {
let #(code, text) = case request {
Request(method: Get, path: "/help", ..)
| Request(method: Get, path: "/", ..) -> #(
200,
"ds100 → Name: " <> baseurl <> "/NN\n" <> "Name → ds100: " <> baseurl <> "/Nürnberg Hbf",
)
Request(method: Get, path: "/" <> path, ..) ->
the_lookup(unpercent(path), stations, ds100s, fuzzy)
_ -> #(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.prepend_header(
"x-sources-at",
"https://stuebinm.eu/git/bahnhof.name",
)
|> response.prepend_header("content-type", "text/plain; charset=utf8")
|> fn (a) { case code == 302 {
True -> response.prepend_header(a, "location", text)
_ -> a
} }
|> 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)
// some ü are corrupted for some reason
Ok(string.replace(response.body, "�", "ü"))
}
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 ref = atom.create_from_string("ref")
let index = index_new(atom.create_from_string("stations"))
|> index_ref(field_term("id"))
|> index_field(field_new("name"))
|> index_add(stations
|> list.map(fn(tuple) {case tuple {
#(name, ds100)
-> map.from_list([#("id", ds100), #("name", name)]
)}}))
let fuzzy = fn(searchterm: String) -> List(String) {
let query = query_new()
let match = atom.create_from_string("match")
let field = atom.create_from_string("field")
let term = atom.create_from_string("term")
let expressions = tokenize(inspect(searchterm))
|> list.filter_map(fn (a) { map.get(a, atom.create_from_string("v")) })
|> list.map(fn (token) { query_expression_new(match, [#(field, "name"), #(term, token)]) })
let clause = query_expressions(clause_new(atom.create_from_string("all")), expressions)
let query = query_clause(query, clause)
let matches = query_run(query, index)
|> list.filter_map(fn (a) { map.get(a, ref) })
inspect(matches)
case list.length(matches) > 5 {
True -> {
let query = query_new()
let clause = query_expressions(
clause_new(atom.create_from_string("all")),
[query_expression_new(match, [#(field, "name"), #(term, "hbf")]) , ..expressions]
)
let query = query_clause(query, clause)
let narrow = query_run(query, index)
|> list.filter_map(fn (a) { map.get(a, ref) })
case narrow {
[] -> matches
_ -> narrow
}
}
_ -> matches
}
}
io.println("compiled index, starting server …")
let _ = mist.run_service(
2345,
fn(req) { lookup_station(req, stationmap, ds100map, baseurl, fuzzy) },
max_body_limit: 100,
)
process.sleep_forever()
}
|