NextBus API for Go

This is an API library for reading data from the NextBus public JSON feed in Go.

import "github.com/cogspace/nextbus"

Things you can do

Get all the agencies NextBus knows about.

agencies, err := nextbus.GetAgencies()

Get all the routes for a given agency.

routes, err := nextbus.GetRoutes("glendale")

Retrieve route information (terse).

routeConfig, err := nextbus.GetRouteConfig("glendale", "12", false, true)

Retrieve schedule information for a route.

schedules, err := nextbus.GetSchedules("glendale", "12")

Get bus predictions for one stop.

predictions, err := nextbus.GetPredictions("glendale", "12", "gtc_d")

Get predictions for multiple stops.

predictions, err := nextbus.GetPredictionsMulti(
    "glendale",
    []nextbus.Stop{
        { Route: "12", Stop: "gtc_d" },
        { Route: "12", Stop: "sanchev" },
    },
)

Nested Types

In the interest of concise, sequential code, some of the types are composed of rather deeply nested anonymous subtypes, for example:

type Schedule struct {
	ServiceClass string
	Title        string
	Tr           []struct {
		Stop []struct {
			Content   string
			Tag       string
			EpochTime string
		}
		BlockId string
	}
	Direction string
	Tag       string
	Header    struct {
		Stop []struct {
			Content string
			Tag     string
		}
	}
	ScheduleClass string
}

The only real problem with this is declaring a type for, say, Tr can be... cumbersome.

func getBlockId(tr struct{ Stop []struct{ Content, Tag, EpochTime string}; BlockId string }) string {
    return tr.BlockId
}

func getStops(tr struct{ Stop []struct{ Content, Tag, EpochTime string }; BlockId string }) []struct{ Content, Tag, EpochTime string } {
    // Now that's just silly...
    return tr.Stop
}

To alleviate this problem, simply name whichever types you need to use.

type Stop struct{ Content, Tag, EpochTime string }
type Tr struct{ Stop []struct{ Content, Tag, EpochTime string }; BlockId string }

func getBlockId(tr Tr) string {
    return tr.BlockId
}

func getStops(tr Tr) []Stop {
    return tr.Stop
}

In practice, naming theses types is not usually necessary in Go client code.

ch := make(chan string)
go func(ch chan string) {
    schedules, err := nextbus.GetSchedules("glendale", "12")
    if err != nil {
        log.Fatal(err)
    }

    for _, schedule := range schedules {
        for _, tr := range schedule.Tr {
            ch <- tr.BlockId
        }
    }
}(ch)
...

Further Reading

The NextBus feed documentation only covers the XML API, but the JSON API is very similar.