Feature: add IFSC service

README.md

@@ -31,6 +31,8 @@ dig fun.dict @dns.toys
 
 dig excuse @dns.toys
 
+dig ABNA0000001.ifsc @dns.toys
+
 dig A12.9352,77.6245/12.9698,77.7500.aerial @dns.toys
 ```
 

cmd/dnstoys/main.go

@@ -19,6 +19,7 @@ import (
 	"github.com/knadh/dns.toys/internal/services/epoch"
 	"github.com/knadh/dns.toys/internal/services/excuse"
 	"github.com/knadh/dns.toys/internal/services/fx"
+	"github.com/knadh/dns.toys/internal/services/ifsc"
 	"github.com/knadh/dns.toys/internal/services/num2words"
 	"github.com/knadh/dns.toys/internal/services/random"
 	"github.com/knadh/dns.toys/internal/services/sudoku"
@@ -346,6 +347,15 @@ func main() {
 		help = append(help, []string{"return a developer excuse", "dig excuse @%s"})
 	}
 
+	if ko.Bool("ifsc.enabled") {
+		e, err := ifsc.New(ko.MustString("ifsc.ifsc_path"))
+		if err != nil {
+			lo.Fatalf("error initializing ifsc service: %v", err)
+		}
+		h.register("ifsc", e, mux)
+		help = append(help, []string{"lookup bank details for IFSC code", "dig ABNA0000001.ifsc @%s"})
+	}
+
 	// Prepare the static help response for the `help` query.
 	for _, l := range help {
 		r, err := dns.NewRR(fmt.Sprintf("help. %d TXT \"%s\" \"%s\"", HELP_TTL, l[0], fmt.Sprintf(l[1], h.domain)))

config.sample.toml

@@ -95,3 +95,11 @@ enabled = true
 [excuse]
 enabled = true
 file = "data/excuses.txt"
+
+[ifsc]
+enabled = true
+
+# You will need to manually download the IFSC data
+# Download from https://github.com/razorpay/ifsc/releases/download/latest/by-bank.tar.gz
+# Untar the folder and save its contents within data/ifsc directory
+ifsc_path = "data/ifsc"

docs/index.html

@@ -215,6 +215,14 @@ <h2>Developer Excuse</h2>
 		<p>Return a developer excuse.</p>
 	</section>
 
+	<section class="box">
+		<h2>Bank details for an IFSC code</h2>
+		<code class="block">
+			<p>dig ABNA0000001.ifsc @dns.toys</p>
+		</code>
+		<p>Lookup bank details for a given IFSC code</p>
+	</section>
+
 	<section class="box">
 		<h2>Help</h2>
 		<code class="block">

internal/services/ifsc/ifsc.go

@@ -0,0 +1,99 @@
+package ifsc
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+const (
+	ifscCodeLen = 11
+)
+
+type Branch struct {
+	Bank string `json:"BANK"`
+	IFSC string `json:"IFSC"`
+	Branch string `json:"BRANCH"`
+	City string `json:"CITY"`
+	State string `json:"STATE"`
+}
+
+type BranchDetails struct {
+	Bank string
+	Branch string
+	City string
+	State string
+}
+
+type IFSC struct {
+	data map[string]BranchDetails
+}
+
+func New(dir string) (*IFSC, error) {
+	// Load IFSCs from disk
+	log.Printf("loading IFSC data from %s", dir)
+	files, err := os.ReadDir(dir)
+	if err != nil {
+		return nil, fmt.Errorf("error accessing IFSC directory: %w", err)
+	}
+
+	var ifsc IFSC
+	ifsc.data = make(map[string]BranchDetails)
+
+	for _, file := range files {
+		var jsonFilePath = filepath.Join(dir, file.Name())
+		jsonFile, err := os.Open(jsonFilePath)
+		if err != nil {
+			return nil, fmt.Errorf("error opening IFSC JSON file: %w", err)
+		}
+		defer jsonFile.Close()
+
+		byteValue, err := io.ReadAll(jsonFile)
+		if err != nil {
+			return nil, fmt.Errorf("error reading IFSC JSON file: %w", err)
+		}
+
+		var branches map[string]Branch	
+		json.Unmarshal(byteValue, &branches)
+
+		for _, v := range branches {
+			ifsc.data[v.IFSC] = BranchDetails{Bank: v.Bank, Branch: v.Branch, City: v.City, State: v.State}
+		}
+	}
+	log.Printf("loaded IFSC data")
+
+	return &ifsc, nil
+}
+
+func (i *IFSC) Query(q string) ([]string, error) {
+	ifscCode := strings.TrimSuffix(q, ".")
+	ifscCode = strings.TrimSuffix(q, ".ifsc")
+	ifscCode = strings.ToUpper(ifscCode)
+
+	if len(ifscCode) != ifscCodeLen {
+		return nil, fmt.Errorf("invalid IFSC code length: %d", len(ifscCode))
+	}
+
+	var output []string
+	value, ok := i.data[ifscCode]
+	if ok {
+		output = []string{
+			fmt.Sprintf(`%s.ifsc. 1 IN TXT "BANK: %s"`, ifscCode, value.Bank), 
+			fmt.Sprintf(`%s.ifsc. 1 IN TXT "BRANCH: %s"`, ifscCode, value.Branch), 
+			fmt.Sprintf(`%s.ifsc. 1 IN TXT "CITY: %s"`, ifscCode, value.City), 
+			fmt.Sprintf(`%s.ifsc. 1 IN TXT "STATE: %s"`, ifscCode, value.State), 
+		}
+	} else {
+		output = []string{fmt.Sprintf(`%s.ifsc. 1 IN TXT "IFSC code %s not found"`, ifscCode, ifscCode)}
+	}
+
+	return output, nil
+}
+
+func (i *IFSC) Dump() ([]byte, error) {
+	return nil, nil
+}