Calling SOAP with Golang

Question

I am new to golang and trying make a soap call with gowsdl .

I have generated the wsdl code and installed it as a package. I am however struggling to understand the syntax for call the method from it.

When I examine the package, this is what I want in the soap body:

type AccountUser struct {
    XMLName xml.Name `xml:"http://exacttarget.com/wsdl/partnerAPI AccountUser"`

    *APIObject

    AccountUserID             int32         `xml:"AccountUserID,omitempty"`
    UserID                    string        `xml:"UserID,omitempty"`
    Password                  string        `xml:"Password,omitempty"`
    Name                      string        `xml:"Name,omitempty"`
    Email                     string        `xml:"Email,omitempty"`
    MustChangePassword        bool          `xml:"MustChangePassword,omitempty"`
    ActiveFlag                bool          `xml:"ActiveFlag,omitempty"`
    ChallengePhrase           string        `xml:"ChallengePhrase,omitempty"`
    ChallengeAnswer           string        `xml:"ChallengeAnswer,omitempty"`
    UserPermissions           []*UserAccess `xml:"UserPermissions,omitempty"`
    Delete                    int32         `xml:"Delete,omitempty"`
    LastSuccessfulLogin       time.Time     `xml:"LastSuccessfulLogin,omitempty"`
    IsAPIUser                 bool          `xml:"IsAPIUser,omitempty"`
    NotificationEmailAddress  string        `xml:"NotificationEmailAddress,omitempty"`
    IsLocked                  bool          `xml:"IsLocked,omitempty"`
    Unlock                    bool          `xml:"Unlock,omitempty"`
    BusinessUnit              int32         `xml:"BusinessUnit,omitempty"`
    DefaultBusinessUnit       int32         `xml:"DefaultBusinessUnit,omitempty"`
    DefaultApplication        string        `xml:"DefaultApplication,omitempty"`
    Locale                    *Locale       `xml:"Locale,omitempty"`
    TimeZone                  *TimeZone     `xml:"TimeZone,omitempty"`
    DefaultBusinessUnitObject *BusinessUnit `xml:"DefaultBusinessUnitObject,omitempty"`

    AssociatedBusinessUnits struct {
        BusinessUnit []*BusinessUnit `xml:"BusinessUnit,omitempty"`
    } `xml:"AssociatedBusinessUnits,omitempty"`

    Roles struct {
        Role []*Role `xml:"Role,omitempty"`
    } `xml:"Roles,omitempty"`

    LanguageLocale *Locale `xml:"LanguageLocale,omitempty"`

    SsoIdentities struct {
        SsoIdentity []*SsoIdentity `xml:"SsoIdentity,omitempty"`
    } `xml:"SsoIdentities,omitempty"`
}

And the method to call the SOAP is :

func (s *SOAPClient) Call(soapAction string, request, response interface{}) error {
    envelope := SOAPEnvelope{
    //Header:        SoapHeader{},
    }

    envelope.Body.Content = request
    buffer := new(bytes.Buffer)

    encoder := xml.NewEncoder(buffer)
    //encoder.Indent("  ", "    ")

    if err := encoder.Encode(envelope); err != nil {
        return err
    }

    if err := encoder.Flush(); err != nil {
        return err
    }

    log.Println(buffer.String())

    req, err := http.NewRequest("POST", s.url, buffer)
    if err != nil {
        return err
    }
    if s.auth != nil {
        req.SetBasicAuth(s.auth.Login, s.auth.Password)
    }

    req.Header.Add("Content-Type", "text/xml; charset=\"utf-8\"")
    if soapAction != "" {
        req.Header.Add("SOAPAction", soapAction)
    }

    req.Header.Set("User-Agent", "gowsdl/0.1")
    req.Close = true

    tr := &http.Transport{
        TLSClientConfig: &tls.Config{
            InsecureSkipVerify: s.tls,
        },
        Dial: dialTimeout,
    }

    client := &http.Client{Transport: tr}
    res, err := client.Do(req)
    if err != nil {
        return err
    }
    defer res.Body.Close()

    rawbody, err := ioutil.ReadAll(res.Body)
    if err != nil {
        return err
    }
    if len(rawbody) == 0 {
        log.Println("empty response")
        return nil
    }

    log.Println(string(rawbody))
    respEnvelope := new(SOAPEnvelope)
    respEnvelope.Body = SOAPBody{Content: response}
    err = xml.Unmarshal(rawbody, respEnvelope)
    if err != nil {
        return err
    }

    fault := respEnvelope.Body.Fault
    if fault != nil {
        return fault
    }

    return nil
}

I have imported the package into my go file , and would love pointers on how to call this.

Answer 1

To use the generated code you obviously will have to first initialize the soap client with one of the generated "constructor" functions NewSOAPClient or NewSOAPClientWithTLSConfig.

After that you'll need to prepare two values that you can use as the request and response arguments to the Call method, they represent the body content of the soap request/response payloads.

The types of those two values will depend on what kind of call you want to make, for example the hypothetical calls create_account, update_account, and delete_account would usually require different types. Basically, the type of the request value should be marshalable into an xml that matches the xml expected by the soap service for the specified action, and the type of the response should be unmarshalable from an xml that matches the soap service's documented response for the specified action.

---

Consider this contrived example:

There is a SOAP service that allows you to create users. For you to be able to create a user with the service it requires you to send an email and a password, and if everyting's ok it will return an id. In such a case your two request/response types would look like this:

type CreateUserRequest struct {
    Email    string `xml:"Email,omitempty"`
    Password string `xml:"Password,omitempty"`
}

type CreateUserResponse struct {
    ID string `xml:"ID"`
}

Then the client code would look like this:

client := NewSOAPClient("https://soap.example.com/call", true, nil)

req := &CreateUserRequest{
    Email:    "[email protected]",
    Password: "1234567890",
}
res := &CreateUserResponse{}
if err := client.Call("create_user", req, res); err != nil {
    panic(err)
}

// if everything went well res.ID should have its
// value set with the one returned by the service.
fmt.Println(res.ID)