yodlee-go

A swagger-go generated Yodlee client library, that is manually fixed so that it compiles, for Golang with an example of how to use it.

Motivation

swagger-go generates code from the yodlee swagger spec that does not compile. Additionally, constructing the Yodlee JWS token in Golang requires some finess.

Example usage

For this to work, you need to set the YODLEE_SANDBOX_PRIVATE_KEY and YODLEE_SANDBOX_ISSUER_ID environment variables as well as the <USER_ID> string to variables from your system.

package main

import (
	"encoding/pem"
	"log"
	"net/http"
	"os"
	"time"

	"crypto"
	"crypto/rand"
	"crypto/rsa"
	"crypto/sha512"
	"crypto/x509"

	"github.com/go-openapi/strfmt"

	"golang.org/x/oauth2/jws"

	yodlee "github.com/propertechnologies/yodlee-go/client"
	"github.com/propertechnologies/yodlee-go/client/accounts"

	httptransport "github.com/go-openapi/runtime/client"
)

type YodleeRoundTripper struct {
	r http.RoundTripper
}

// Api-Version header must be manually added to all requests
func (rt YodleeRoundTripper) RoundTrip(r *http.Request) (*http.Response, error) {
	r.Header.Add("Api-Version", "1.1")
	return rt.r.RoundTrip(r)
}

func main() {
	// This string MUST have newline characters before and after "-----BEGIN PRIVATE KEY------" 
	// or it won't parse. If you see \n characters in the printf, you didn't export the vars correctly.
	os.Getenv("YODLEE_SANDBOX_PRIVATE_KEY")
	log.Printf("key = \n%s", k)
	key := []byte(k)

	claims := &jws.ClaimSet{
		Iss: os.Getenv("YODLEE_SANDBOX_ISSUER_ID"),
		Iat: time.Now().Unix(),
		Exp: time.Now().Unix() + 1800,
		Sub: "<USER_ID>",
	}
	headers := &jws.Header{
		Algorithm: "RS512",
		Typ:       "JWT",
	}
	var err error
	privPem, _ := pem.Decode(key)

	var parsedKey interface{}
	if parsedKey, err = x509.ParsePKCS8PrivateKey(privPem.Bytes); err != nil {
		panic(err)
	}

	var privateKey *rsa.PrivateKey
	var ok bool
	privateKey, ok = parsedKey.(*rsa.PrivateKey)
	if !ok {
		panic("Failed to parse key")
	}
	// We need to create a custom signer, the default one uses sha256, yodlee uses sha512
	sg := func(data []byte) (sig []byte, err error) {
		h := sha512.New()
		h.Write(data)
		return rsa.SignPKCS1v15(rand.Reader, privateKey, crypto.SHA512, h.Sum(nil))
	}
	ss, err := jws.EncodeWithSigner(headers, claims, sg)
	if err != nil {
		panic(err)
	}
	// This endpoint will change depending on environment
	t := httptransport.New("sandbox.api.yodlee.com", "/ysl", []string{"https"})
	var yRoundTripper http.RoundTripper = YodleeRoundTripper{r: http.DefaultTransport}
	t.Transport = yRoundTripper
	t.DefaultAuthentication = httptransport.BearerToken(ss)
	c := yodlee.New(t, strfmt.Default)

	resp, err := c.Accounts.GetAllAccounts(accounts.NewGetAllAccountsParams())
	if err != nil {
		panic(err)
	}
	log.Printf("accounts = %+v\n", resp.Payload)
	log.Printf("error = %s\n", resp.Error())
}