Add powerful match subcommand to cmdline client

- Multiple output formats
- Signals matches via exit status for shell scripts
- Match against To, From, Subject via regular expressions
- Can optionally delete matched messages

cmd/client/match.go

@@ -0,0 +1,141 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"os"
+
+	"github.com/google/subcommands"
+	"github.com/jhillyerd/inbucket/rest/client"
+)
+
+type matchCmd struct {
+	mailbox string
+	output  string
+	outFunc func(headers []*client.MessageHeader) error
+	delete  bool
+	from    regexFlag
+	subject regexFlag
+	to      regexFlag
+}
+
+func (*matchCmd) Name() string {
+	return "match"
+}
+
+func (*matchCmd) Synopsis() string {
+	return "output messages matching criteria"
+}
+
+func (*matchCmd) Usage() string {
+	return `match [options] <mailbox>:
+	output messages matching all specified criteria
+	exit status will be 1 if no matches were found, otherwise 0
+`
+}
+
+func (m *matchCmd) SetFlags(f *flag.FlagSet) {
+	f.StringVar(&m.output, "output", "id", "output format: id, json, or mbox")
+	f.BoolVar(&m.delete, "delete", false, "delete matched messages after output")
+	f.Var(&m.from, "from", "From header matching regexp")
+	f.Var(&m.subject, "subject", "Subject header matching regexp")
+	f.Var(&m.to, "to", "To header matching regexp (must match one)")
+}
+
+func (m *matchCmd) Execute(
+	_ context.Context, f *flag.FlagSet, _ ...interface{}) subcommands.ExitStatus {
+	mailbox := f.Arg(0)
+	if mailbox == "" {
+		return usage("mailbox required")
+	}
+	// Select output function
+	switch m.output {
+	case "id":
+		m.outFunc = outputID
+	case "json":
+		m.outFunc = outputJSON
+	case "mbox":
+		m.outFunc = outputMbox
+	default:
+		return usage("unknown output type: " + m.output)
+	}
+	// Setup REST client
+	c, err := client.New(baseURL())
+	if err != nil {
+		return fatal("Couldn't build client", err)
+	}
+	// Get list
+	headers, err := c.ListMailbox(mailbox)
+	if err != nil {
+		return fatal("List REST call failed", err)
+	}
+	// Find matches
+	matches := make([]*client.MessageHeader, 0, len(headers))
+	for _, h := range headers {
+		if m.match(h) {
+			matches = append(matches, h)
+		}
+	}
+	// Return error status if no matches
+	if len(matches) == 0 {
+		return subcommands.ExitFailure
+	}
+	// Output matches
+	err = m.outFunc(matches)
+	if err != nil {
+		return fatal("Error", err)
+	}
+	if m.delete {
+		// Delete matches
+		for _, h := range matches {
+			err = h.Delete()
+			if err != nil {
+				return fatal("Delete REST call failed", err)
+			}
+		}
+	}
+	return subcommands.ExitSuccess
+}
+
+// match returns true if header matches all defined criteria
+func (m *matchCmd) match(header *client.MessageHeader) bool {
+	if m.subject.Defined() {
+		if !m.subject.MatchString(header.Subject) {
+			return false
+		}
+	}
+	if m.from.Defined() {
+		if !m.from.MatchString(header.From) {
+			return false
+		}
+	}
+	if m.to.Defined() {
+		match := false
+		for _, to := range header.To {
+			if m.to.MatchString(to) {
+				match = true
+				break
+			}
+		}
+		if !match {
+			return false
+		}
+	}
+	return true
+}
+
+func outputID(headers []*client.MessageHeader) error {
+	for _, h := range headers {
+		fmt.Println(h.ID)
+	}
+	return nil
+}
+
+func outputJSON(headers []*client.MessageHeader) error {
+	jsonEncoder := json.NewEncoder(os.Stdout)
+	jsonEncoder.SetEscapeHTML(false)
+	jsonEncoder.SetIndent("", "  ")
+	return jsonEncoder.Encode(headers)
+}