Impove Jsonpath matcher

* Simplifed mass jsonpath extractions json document

csaf/summary.go

@@ -9,7 +9,6 @@
 package csaf
 
 import (
-	"errors"
 	"time"
 
 	"github.com/csaf-poc/csaf_distribution/util"
@@ -36,83 +35,28 @@ type AdvisorySummary struct {
 	TLPLabel           string
 }
 
-type extractFunc func(string) (interface{}, error)
-
 // NewAdvisorySummary creates a summary from an advisory doc
 // with the help of an expression evaluator expr.
 func NewAdvisorySummary(
-	expr *util.PathEval,
+	pe *util.PathEval,
 	doc interface{},
 ) (*AdvisorySummary, error) {
 
-	e := new(AdvisorySummary)
-
-	path := func(s string) (interface{}, error) {
-		return expr.Eval(s, doc)
+	e := &AdvisorySummary{
+		Publisher: new(Publisher),
 	}
 
-	for _, fn := range []func(extractFunc) error{
-		extractText(idExpr, &e.ID),
-		extractText(titleExpr, &e.Title),
-		extractTime(currentReleaseDateExpr, &e.CurrentReleaseDate),
-		extractTime(initialReleaseDateExpr, &e.InitialReleaseDate),
-		extractText(summaryExpr, &e.Summary),
-		extractText(tlpLabelExpr, &e.TLPLabel),
-		e.extractPublisher,
-	} {
-		if err := fn(path); err != nil {
-			return nil, err
-		}
+	if err := pe.Match([]util.PathEvalMatcher{
+		{Expr: idExpr, Action: util.StringMatcher(&e.ID)},
+		{Expr: titleExpr, Action: util.StringMatcher(&e.Title)},
+		{Expr: currentReleaseDateExpr, Action: util.TimeMatcher(&e.CurrentReleaseDate, time.RFC3339)},
+		{Expr: initialReleaseDateExpr, Action: util.TimeMatcher(&e.InitialReleaseDate, time.RFC3339)},
+		{Expr: summaryExpr, Action: util.StringMatcher(&e.Summary)},
+		{Expr: tlpLabelExpr, Action: util.StringMatcher(&e.TLPLabel)},
+		{Expr: publisherExpr, Action: util.ReMarshalMatcher(e.Publisher)},
+	}, doc); err != nil {
+		return nil, err
 	}
 
 	return e, nil
 }
-
-func extractText(expr string, store *string) func(extractFunc) error {
-
-	return func(path extractFunc) error {
-		s, err := path(expr)
-		if text, ok := s.(string); ok && err == nil {
-			*store = text
-		}
-		return nil
-	}
-}
-
-func extractTime(expr string, store *time.Time) func(extractFunc) error {
-
-	return func(path extractFunc) error {
-		s, err := path(expr)
-		if err != nil {
-			return err
-		}
-		text, ok := s.(string)
-		if !ok {
-			return errors.New("not a string")
-		}
-		date, err := time.Parse(time.RFC3339, text)
-		if err == nil {
-			*store = date.UTC()
-		}
-		return err
-	}
-}
-
-func (e *AdvisorySummary) extractPublisher(path extractFunc) error {
-	p, err := path(publisherExpr)
-	if err != nil {
-		return err
-	}
-
-	// XXX: It's a bit cumbersome to serialize and deserialize
-	// it into our own structure.
-	publisher := new(Publisher)
-	if err := util.ReMarshalJSON(publisher, p); err != nil {
-		return err
-	}
-	if err := publisher.Validate(); err != nil {
-		return err
-	}
-	e.Publisher = publisher
-	return nil
-}

util/json.go

@@ -12,6 +12,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"time"
 
 	"github.com/PaesslerAG/gval"
 	"github.com/PaesslerAG/jsonpath"
@@ -56,3 +57,61 @@ func (pe *PathEval) Eval(expr string, doc interface{}) (interface{}, error) {
 	}
 	return eval(context.Background(), doc)
 }
+
+// PathEvalMatcher is a pair of an expression and an action
+// when doing extractions via PathEval.Match.
+type PathEvalMatcher struct {
+	// Expr is the expression to evaluate
+	Expr string
+	// Action is executed with the result of the match.
+	Action func(interface{}) error
+}
+
+// ReMarshalMatcher is an action to re-marshal the result to another type.
+func ReMarshalMatcher(dst interface{}) func(interface{}) error {
+	return func(src interface{}) error {
+		return ReMarshalJSON(dst, src)
+	}
+}
+
+// StringMatcher stores the matched result in a string.
+func StringMatcher(dst *string) func(interface{}) error {
+	return func(x interface{}) error {
+		s, ok := x.(string)
+		if !ok {
+			return errors.New("not a string")
+		}
+		*dst = s
+		return nil
+	}
+}
+
+// TimeMatcher stores a time with a given format.
+func TimeMatcher(dst *time.Time, format string) func(interface{}) error {
+	return func(x interface{}) error {
+		s, ok := x.(string)
+		if !ok {
+			return errors.New("not a string")
+		}
+		t, err := time.Parse(format, s)
+		if err != nil {
+			return nil
+		}
+		*dst = t
+		return nil
+	}
+}
+
+// Match matches a list of PathEvalMatcher pairs against a document.
+func (pe *PathEval) Match(matcher []PathEvalMatcher, doc interface{}) error {
+	for _, m := range matcher {
+		x, err := pe.Eval(m.Expr, doc)
+		if err != nil {
+			return err
+		}
+		if err := m.Action(x); err != nil {
+			return err
+		}
+	}
+	return nil
+}