1package content
  2
  3import (
  4	"encoding/json"
  5	"net/url"
  6	"time"
  7)
  8
  9// Observation is a specific discussion/permalink that points at an Item's URL
 10type Observation struct {
 11	Id  URLID    // Observation URLID
 12	URL *url.URL // Observation URL
 13
 14	TargetURL     *url.URL
 15	DiscussionURL *url.URL
 16
 17	Title      string
 18	SourceName string
 19	Seen       time.Time
 20}
 21
 22func NewObservation(
 23	observationURL *url.URL,
 24	targetURL *url.URL,
 25	discussionURL *url.URL,
 26	sourceName string,
 27	title string,
 28) (*Observation, error) {
 29
 30	id, err := NewURLID(observationURL)
 31	if err != nil {
 32		return nil, err
 33	}
 34	return &Observation{
 35		Id:  id,
 36		URL: observationURL,
 37
 38		TargetURL:     targetURL,
 39		DiscussionURL: discussionURL,
 40
 41		Title:      title,
 42		SourceName: sourceName,
 43		Seen:       time.Now(),
 44	}, nil
 45}
 46
 47// MarshalJSON allows for stringified urls in marshaled Observation type
 48// satisfies the json.Marshaler interface
 49func (obs *Observation) MarshalJSON() ([]byte, error) {
 50	o := struct {
 51		Id  URLID  `json:"id"`
 52		URL string `json:"url"`
 53
 54		TargetURL     string `json:"target_url"`
 55		DiscussionURL string `json:"discussion_url,omitempty"`
 56
 57		SourceName string    `json:"source_name"`
 58		Seen       time.Time `json:"seen"`
 59		Title      string    `json:"title,omitempty"`
 60	}{
 61		Id:  obs.Id,
 62		URL: obs.URL.String(),
 63
 64		TargetURL:     obs.TargetURL.String(),
 65		DiscussionURL: obs.DiscussionURL.String(),
 66
 67		SourceName: obs.SourceName,
 68		Seen:       obs.Seen,
 69		Title:      obs.Title,
 70	}
 71	return json.Marshal(&o)
 72}
 73
 74// UnmarshalJSON parses string urls from the json bytes to url.URL where needed
 75// satisfies the json.Unmarshaler interface
 76func (obs *Observation) UnmarshalJSON(data []byte) error {
 77	o := struct {
 78		Id  URLID  `json:"id"`
 79		URL string `json:"url"`
 80
 81		TargetURL     string `json:"target_url"`
 82		DiscussionURL string `json:"discussion_url,omitempty"`
 83
 84		SourceName string    `json:"source_name"`
 85		Seen       time.Time `json:"seen"`
 86		Title      string    `json:"title,omitempty"`
 87	}{}
 88	err := json.Unmarshal(data, &o)
 89	if err != nil {
 90		return err
 91	}
 92
 93	obsURL, err := url.Parse(o.URL)
 94	if err != nil {
 95		return err
 96	}
 97	obs.Id = o.Id
 98	obs.URL = obsURL
 99
100	targetURL, err := url.Parse(o.TargetURL)
101	if err != nil {
102		return err
103	}
104	obs.TargetURL = targetURL
105
106	if o.DiscussionURL != "" {
107		discussionURL, err := url.Parse(o.DiscussionURL)
108		if err != nil {
109			return err
110		}
111		obs.DiscussionURL = discussionURL
112	}
113
114	obs.SourceName = o.SourceName
115	obs.Seen = o.Seen
116	obs.Title = o.Title
117
118	return nil
119}