point-tools-crawler/point/client.go

package point

import (
	"log"
	"net/http"
	"net/url"
	"io/ioutil"
	"encoding/json"
	"errors"
	"strings"
	"strconv"
)

const point_api_url string = "https://point.im/api/"

type Client struct {
	token Token
}

func (c *Client) getResponseBody(resp *http.Response) ([]byte, error) {
	body, read_err := ioutil.ReadAll(resp.Body)

	if read_err != nil {
		log.Fatal(read_err)
		return nil, read_err
	}

	return body, nil
}

func (c *Client) MakeGetRequest(url string, params *url.Values) ([]byte, error) {
	var body []byte

	if params != nil {
		url += "?" + params.Encode()
	}

	req, req_err := http.NewRequest("GET", url, nil)

	if req_err != nil {
		log.Fatal(req_err)
		return body, req_err
	}

	if len(c.token.AuthToken) > 0 {
		req.Header.Set("Authorization", c.token.AuthToken)
	}

	hc := &http.Client{}

	resp, resp_err := hc.Do(req)

	if resp_err != nil {
		log.Fatal(resp_err)
		return nil, resp_err
	}

	defer resp.Body.Close()

	body, read_err := c.getResponseBody(resp)

	if read_err != nil {
		return nil, read_err
	}

	return body, nil
}

func (c *Client) MakePostRequest(url string, params url.Values) ([]byte, error) {
	req, req_err := http.NewRequest("POST", url, strings.NewReader(params.Encode()))

	if req_err != nil {
		log.Fatal(req_err)
		return nil, req_err
	}

	hc := &http.Client{}

	if len(c.token.AuthToken) > 0 {
		req.Header.Set("Authorization", c.token.AuthToken)
	}

	// Adding necessary for POST request header
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")

	resp, resp_err := hc.Do(req)

	if resp_err != nil {
		log.Fatal(resp_err)
		return nil, resp_err
	}

	body, read_err := c.getResponseBody(resp)

	if read_err != nil {
		return nil, read_err
	}

	return body, nil
}

func (c *Client) Login(login, password string) (Token, error) {
	var token Token

	data := url.Values{}
	data.Add("login", login)
	data.Add("password", password)

	body, req_err := c.MakePostRequest(point_api_url + "login", data)

	if req_err != nil {
		return token, req_err
	}

	json_err := json.Unmarshal(body, &token)

	if json_err != nil {
		log.Fatal(json_err)
		return token, errors.New("JSON deserialization error")
	}

	if token.Error != "" {
		return token, errors.New(token.Error)
	}

	c.token = token

	return token, nil
}

func (c *Client) GetRecentAllPostsPage() (Page, error) {
	var page Page

	if len(c.token.AuthToken) == 0 {
		log.Fatal("Can not get recent posts. Login first.")
		return page, errors.New("Login first")
	}

	body, req_err := c.MakeGetRequest(point_api_url + "all", nil)

	if req_err != nil {
		return page, errors.New("HTTP request error")
	}

	json_err := json.Unmarshal(body, &page)

	if json_err != nil {
		log.Fatal(json_err)
		return page, errors.New("JSON deserialization error")
	}

	// Move page.Error to response object
	if page.Error == "NotAuthorized" {
		log.Fatal("Please use correct login and password to fetch recent posts")
		return page, errors.New("Not authorized")
	}

	return page, nil
}

func (c *Client) GetNextAllPostsPage(page Page) (Page, error) {
	var nextPage Page

	if false == page.HasNext || len(page.Posts) == 0 {
		return nextPage, errors.New("Page must have has_next=true and some posts")
	}

	if len(c.token.AuthToken) == 0 {
		log.Fatal("Can not get recent posts. Login first.")
		return nextPage, errors.New("Login first")
	}

	data := url.Values{}
	data.Add("before", strconv.Itoa(page.Posts[len(page.Posts)-1].Uid))

	body, req_err := c.MakeGetRequest(point_api_url + "all", &data)

	if req_err != nil {
		return nextPage, errors.New("HTTP request error")
	}

	json_err := json.Unmarshal(body, &nextPage)

	if json_err != nil {
		log.Fatal(json_err)
		return nextPage, errors.New("JSON deserialization error")
	}

	// Move page.Error to response object
	if nextPage.Error == "NotAuthorized" {
		log.Fatal("Please use correct login and password to fetch recent posts")
		return nextPage, errors.New("Not authorized")
	}

	return nextPage, nil
}