CMSgov/dpc-app

package lib

import (
    "encoding/json"
    "fmt"
    "io/ioutil"
    "log"
    "net/http"
    "net/url"
)

func ReadSmallFile(path string) ([]byte, error) {
    // These files should never be large enough to require buffering
    /* #nosec -- Potential file inclusion via variable */
    data, err := ioutil.ReadFile(path)
    if err != nil {
        return nil, err
    }
    return data, nil
}

func WriteSmallFile(path string, content []byte) error {
    // These files should never be large enough to require buffering
    /* #nosec -- Potential file inclusion via variable */
    if err := ioutil.WriteFile(path, content, 0644); err != nil {
        return err
    }
    return nil
}

func GetAccessToken(authTokenBytes []byte, baseURL string) (string, error) {
    data := url.Values{}
    data.Set("grant_type", "client_credentials")
    data.Set("scope", "system/*.*")
    data.Set("client_assertion_type", "urn:ietf:params:oauth:client-assertion-type:jwt-bearer")
    data.Set("client_assertion", string(authTokenBytes))

    resp, err := http.PostForm(fmt.Sprintf("%s/Token/auth", baseURL), data)
    // make sure we close the body if necessary when there's an error
    if resp != nil {
        defer func() {
            err = resp.Body.Close()
            if err != nil {
                log.Fatalf("error closing request to %s: %s", resp.Request.URL, err)
            }
        }()
    }
    if err != nil {
        return "", err
    }

    if resp.StatusCode != 200 {
        msg, _ := ioutil.ReadAll(resp.Body)
        return "", fmt.Errorf("status %d, %s", resp.StatusCode, msg)
    }

    type TokenResponse struct {
        Scope       string `json:"scope"`
        AccessToken string `json:"access_token"`
        TokenType   string `json:"token_type"`
        ExpiresIn   int64  `json:"expires_in"`
    }
    var t TokenResponse
    if err = json.NewDecoder(resp.Body).Decode(&t); err != nil {
        panic(fmt.Sprintf("unexpected token response format: %s", err.Error()))
    }
    //fmt.Printf("TokenResponse: %+v", t)

    return t.AccessToken, nil
}