go-latestver/internal/fetcher/json.go
Knut Ahlers 02ec355192
Implement json and atlassian fetchers
Signed-off-by: Knut Ahlers <knut@ahlers.me>
2021-11-29 16:53:15 +01:00

109 lines
2.9 KiB
Go

package fetcher
import (
"bytes"
"context"
"io/ioutil"
"net/http"
"regexp"
"time"
"github.com/antchfx/jsonquery"
"github.com/antchfx/xpath"
"github.com/pkg/errors"
"github.com/Luzifer/go-latestver/internal/database"
"github.com/Luzifer/go_helpers/v2/fieldcollection"
)
var (
jsonFetcherDefaultRegex = `(v?(?:[0-9]+\.?){2,})`
jsonpStripRegex = regexp.MustCompile(`(?m)^[^\(]+\((.*)\)$`)
ptrBoolFalse = func(v bool) *bool { return &v }(false)
)
type (
JSONFetcher struct{}
)
func init() { registerFetcher("json", func() Fetcher { return &JSONFetcher{} }) }
func (JSONFetcher) FetchVersion(ctx context.Context, attrs *fieldcollection.FieldCollection) (string, time.Time, error) {
var (
doc *jsonquery.Node
err error
)
if attrs.MustBool("jsonp", ptrBoolFalse) {
req, err := http.NewRequestWithContext(ctx, http.MethodGet, attrs.MustString("url", nil), nil)
if err != nil {
return "", time.Time{}, errors.Wrap(err, "creating request")
}
resp, err := http.DefaultClient.Do(req)
if err != nil {
return "", time.Time{}, errors.Wrap(err, "executing request")
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return "", time.Time{}, errors.Wrap(err, "reading response body")
}
matches := jsonpStripRegex.FindSubmatch(body)
if matches == nil {
return "", time.Time{}, errors.New("document does not match jsonp syntax")
}
doc, err = jsonquery.Parse(bytes.NewReader(matches[1]))
} else {
doc, err = jsonquery.LoadURL(attrs.MustString("url", nil))
}
if err != nil {
return "", time.Time{}, errors.New("parsing JSON document")
}
node, err := jsonquery.Query(doc, attrs.MustString("xpath", nil))
if err != nil {
return "", time.Time{}, errors.Wrap(err, "querying xpath")
}
if node == nil {
return "", time.Time{}, errors.New("xpath expression lead to nil-node")
}
if node.Type == jsonquery.ElementNode && node.FirstChild != nil && node.FirstChild.Type == jsonquery.TextNode {
node = node.FirstChild
}
if node.Type != jsonquery.TextNode {
return "", time.Time{}, errors.Errorf("xpath expression lead to unexpected node type: %d", node.Type)
}
match := regexp.MustCompile(attrs.MustString("regex", &jsonFetcherDefaultRegex)).FindStringSubmatch(node.Data)
if len(match) < 2 {
return "", time.Time{}, errors.New("regular expression did not yield version")
}
return match[1], time.Now(), nil
}
func (JSONFetcher) Links(attrs *fieldcollection.FieldCollection) []database.CatalogLink { return nil }
func (JSONFetcher) Validate(attrs *fieldcollection.FieldCollection) error {
if v, err := attrs.String("url"); err != nil || v == "" {
return errors.New("url is expected to be non-empty string")
}
if v, err := attrs.String("xpath"); err != nil || v == "" {
return errors.New("xpath is expected to be non-empty string")
}
if _, err := xpath.Compile(attrs.MustString("xpath", nil)); err != nil {
return errors.Wrap(err, "compiling xpath expression")
}
return nil
}