timetable-mgr/nrod/streams.go

package nrod

import (
	"compress/gzip"
	"errors"
	"fmt"
	"io"
	"net/http"
	"time"

	"git.fjla.uk/owlboard/timetable-mgr/helpers"
	"git.fjla.uk/owlboard/timetable-mgr/log"
	"go.uber.org/zap"
)

// Downloads NROD Data and extracts if GZIP, returns a io.Reader
func NrodStream(url string, cfg *helpers.Configuration) (io.ReadCloser, error) {
	log.Debug("Fetching NROD data stream", zap.String("Request URL", url))

	client := http.Client{
		Timeout: time.Second * 300,
	}

	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return nil, err
	}

	req.Header.Add("Authorization", "Basic "+helpers.BasicAuth(cfg.NrodUser, cfg.NrodPass))

	resp, err := client.Do(req)
	if err != nil {
		log.Error("Error carrying out HTTP Request", zap.Error(err))
		return nil, err
	}

	if resp == nil {
		err = errors.New("http response error - response = nil")
		return nil, err
	}

	if resp.StatusCode != http.StatusOK {
		err := fmt.Errorf("unexpected status code: %d", resp.StatusCode)
		return nil, err
	}

	// Run the data through the extractor function and return io.ReadCloser, error from
	// that function directly
	return NrodStreamExtract(resp)
}

func NrodStreamExtract(resp *http.Response) (io.ReadCloser, error) {
	log.Debug("Extracting NROD Download")

	log.Debug("Content Type", zap.String("Content-Encoding", resp.Header.Get("Content-Encoding")))

	gzReader, err := gzip.NewReader(resp.Body)
	if err != nil {
		log.Warn("Unable to create GZIP Reader, data probably not gzipped")
		return resp.Body, err
	}

	return gzReader, nil
}