zephinzer/dev

package oauth

import (
    "encoding/json"
    "errors"
    "fmt"
)

type GrantResponseKey string

const (
    GrantResponseAccessToken GrantResponseKey = "grant_response_access_token_key"
    GrantResponseError       GrantResponseKey = "grant_response_error"
    GrantResponseScope       GrantResponseKey = "grant_response_scope_key"
    GrantResponseTokenType   GrantResponseKey = "grant_response_type_key"
)

var (
    DefaultGrantResponseMapping map[GrantResponseKey]string = map[GrantResponseKey]string{
        GrantResponseAccessToken: "access_token",
        GrantResponseError:       "error",
        GrantResponseScope:       "scope",
        GrantResponseTokenType:   "token_type",
    }
)

// GrantResponse represents the response to the request
// by the application to exchange an authorization code for an
// access token
type GrantResponse struct {
    AccessToken string
    Scope       string
    TokenType   string
    Error       error
}

// LoadFromJSON parses the provided JSON-formatted responseBody into a GrantResponse instance
func (r *GrantResponse) LoadFromJSON(responseBody []byte, mapping ...map[GrantResponseKey]string) error {
    responseFieldMap := DefaultGrantResponseMapping
    if len(mapping) > 0 {
        responseFieldMap = mapping[0]
    }
    var unmarshalledResponse map[string]interface{}
    unmarshalError := json.Unmarshal(responseBody, &unmarshalledResponse)
    if unmarshalError != nil {
        return fmt.Errorf("failed to parse response '%s': %s", string(responseBody), unmarshalError)
    }
    var ok bool
    var err string
    if err, ok = unmarshalledResponse[responseFieldMap[GrantResponseError]].(string); ok {
        r.Error = errors.New(err)
        return nil
    }
    if r.AccessToken, ok = unmarshalledResponse[responseFieldMap[GrantResponseAccessToken]].(string); !ok {
        return fmt.Errorf("failed to retrieve the access-token field using key '%s'", responseFieldMap[GrantResponseAccessToken])
    }
    if r.Scope, ok = unmarshalledResponse[responseFieldMap[GrantResponseScope]].(string); !ok {
        return fmt.Errorf("failed to retrieve the scope field using key '%s'", responseFieldMap[GrantResponseScope])
    }
    if r.TokenType, ok = unmarshalledResponse[responseFieldMap[GrantResponseTokenType]].(string); !ok {
        return fmt.Errorf("failed to retrieve the token-type field using key '%s'", responseFieldMap[GrantResponseTokenType])
    }
    return nil
}