package osm import ( "bytes" "encoding/xml" "fmt" "io" "io/ioutil" "net/http" "strconv" "time" ) const ( liveAPIBaseURL = "http://api.openstreetmap.org/api/0.6" devAPIBaseURL = "http://api06.dev.openstreetmap.org/api/0.6" ) // Client represents an OSM client which is capable of RW operations on the OpenStreetMap type Client struct { username string password string APIBaseURL string HTTPClient *http.Client CurrentUser *User } // New instantiates a new client and retrieves information about the current user. Set useDevServer to true to change the API URL to the api06.dev.openstreetmap.org server. func New(username, password string, useDevServer bool) (*Client, error) { out := &Client{ username: username, password: password, APIBaseURL: liveAPIBaseURL, HTTPClient: http.DefaultClient, } if useDevServer { out.APIBaseURL = devAPIBaseURL } u := &Wrap{User: &User{}} if err := out.doParse("GET", "/user/details", nil, u); err != nil { return nil, err } out.CurrentUser = u.User return out, nil } func (c *Client) doPlain(method, path string, body io.Reader) (string, error) { responseBody, err := c.do(method, path, body) if err != nil { return "", err } defer responseBody.Close() data, err := ioutil.ReadAll(responseBody) if err != nil { return "", err } return string(data), nil } func (c *Client) do(method, path string, body io.Reader) (io.ReadCloser, error) { req, _ := http.NewRequest(method, c.APIBaseURL+path, body) req.SetBasicAuth(c.username, c.password) res, err := c.HTTPClient.Do(req) if err != nil { return nil, err } if res.StatusCode != http.StatusOK { d, e := ioutil.ReadAll(res.Body) if e != nil { return nil, fmt.Errorf("OSM API responded with status code %d and reading response failed", res.StatusCode) } res.Body.Close() return nil, fmt.Errorf("OSM API responded with status code %d (%s)", res.StatusCode, d) } return res.Body, nil } func (c *Client) doParse(method, path string, body io.Reader, output interface{}) error { responseBody, err := c.do(method, path, body) if err != nil { return err } defer responseBody.Close() if output != nil { return xml.NewDecoder(responseBody).Decode(output) } return nil } // Wrap is a mostly internal used struct which holds requests to / responses from the API. // You will get a Wrap object when querying map objects from the API type Wrap struct { XMLName xml.Name `xml:"osm"` User *User `xml:"user,omitempty"` Changesets []*Changeset `xml:"changeset,omitempty"` Nodes []*Node `xml:"node,omitempty"` } // Changeset contains information about a changeset in the API. You need to create a changeset before submitting any changes to the API. type Changeset struct { XMLName xml.Name `xml:"changeset"` ID int64 `xml:"id,attr,omitempty"` User string `xml:"user,attr,omitempty"` UID int64 `xml:"uid,attr,omitempty"` CreatedAt time.Time `xml:"created_at,attr,omitempty"` ClosedAt time.Time `xml:"closed_at,attr,omitempty"` Open bool `xml:"open,attr,omitempty"` MinLat float64 `xml:"min_lat,attr,omitempty"` MinLon float64 `xml:"min_lon,attr,omitempty"` MaxLat float64 `xml:"max_lat,attr,omitempty"` MaxLon float64 `xml:"max_lon,attr,omitempty"` CommentCount int64 `xml:"comments_count,attr,omitempty"` Tags []Tag `xml:"tag"` } // GetMyChangesets retrieves a list of (open) changesets from the API func (c *Client) GetMyChangesets(onlyOpen bool) ([]*Changeset, error) { urlPath := fmt.Sprintf("/changesets?user=%d&open=%s", c.CurrentUser.ID, strconv.FormatBool(onlyOpen)) r := &Wrap{} return r.Changesets, c.doParse("GET", urlPath, nil, r) } // CreateChangeset creates a new changeset func (c *Client) CreateChangeset() (*Changeset, error) { body := bytes.NewBuffer([]byte{}) if err := xml.NewEncoder(body).Encode(Wrap{Changesets: []*Changeset{{}}}); err != nil { return nil, err } res, err := c.doPlain("PUT", "/changeset/create", body) if err != nil { return nil, err } cs := &Wrap{} if err := c.doParse("GET", fmt.Sprintf("/changeset/%s", res), nil, cs); err != nil { return nil, err } if len(cs.Changesets) != 1 { return nil, fmt.Errorf("Unable to retrieve new changeset #%s", res) } return cs.Changesets[0], nil } // SaveChangeset updates or creates a changeset func (c *Client) SaveChangeset(cs *Changeset) error { urlPath := "/changeset/create" if cs.ID > 0 { urlPath = fmt.Sprintf("/changeset/%d", cs.ID) } data := Wrap{Changesets: []*Changeset{cs}} body := bytes.NewBuffer([]byte{}) if err := xml.NewEncoder(body).Encode(data); err != nil { return err } _, err := c.doPlain("PUT", urlPath, body) return err } // RetrieveMapObjects queries all objects within the passed bounds. You need to ensure the min values are below the max values. func (c *Client) RetrieveMapObjects(minLat, minLon, maxLat, maxLon float64) (*Wrap, error) { urlPath := fmt.Sprintf("/map?bbox=%.7f,%.7f,%.7f,%.7f", minLat, minLon, maxLat, maxLon) res := &Wrap{} return res, c.doParse("GET", urlPath, nil, res) } // User contains information about an User in the OpenStreetMap type User struct { XMLName xml.Name `xml:"user"` ID int64 `xml:"id,attr"` DisplayName string `xml:"display_name,attr"` AccountCreated time.Time `xml:"account_created,attr"` Description string `xml:"description"` } // Node represents one node in the OpenStreetMap type Node struct { XMLName xml.Name `xml:"node"` ID int64 `xml:"id,attr,omitempty"` Version int64 `xml:"version,attr,omitempty"` Changeset int64 `xml:"changeset,attr,omitempty"` User string `xml:"user,attr,omitempty"` UID int64 `xml:"uid,attr,omitempty"` Latitude float64 `xml:"lat,attr"` Longitude float64 `xml:"lon,attr"` Tags []Tag `xml:"tag"` } // SaveNode creates or updates a node with an association to the passed changeset which needs to be open and known to the API. func (c *Client) SaveNode(n *Node, cs *Changeset) error { if n.ID > 0 && n.Version == 0 { return fmt.Errorf("When an ID is set the version must be present") } urlPath := "/node/create" if n.ID > 0 { urlPath = fmt.Sprintf("/node/%d", n.ID) } n.Changeset = cs.ID data := Wrap{Nodes: []*Node{n}} body := bytes.NewBuffer([]byte{}) if err := xml.NewEncoder(body).Encode(data); err != nil { return err } _, err := c.doPlain("PUT", urlPath, body) return err } // Tag represents a key-value pair used in all objects inside OpenStreetMap type Tag struct { XMLName xml.Name `xml:"tag"` Key string `xml:"k,attr"` Value string `xml:"v,attr"` }