request.go

package web

import (
    "fmt"
    "http"
    "io"
    "io/ioutil"
    "json"
    "mime"
    "mime/multipart"
    "net"
    "os"
    "reflect"
    "strconv"
    "strings"
    "url"
)

type filedata struct {
    Filename string
    Data     []byte
}

type Request struct {
    Method     string   // GET, POST, PUT, etc.
    RawURL     string   // The raw URL given in the request.
    URL        *url.URL // Parsed URL.
    Proto      string   // "HTTP/1.0"
    ProtoMajor int      // 1
    ProtoMinor int      // 0
    Headers    http.Header
    Body       io.Reader
    Close      bool
    Host       string
    Referer    string
    UserAgent  string
    FullParams map[string][]string
    Params     map[string]string
    ParamData  []byte
    Cookies    map[string]string
    Cookie     []*http.Cookie
    Files      map[string]filedata
    RemoteAddr string
    RemotePort int
}

type badStringError struct {
    what string
    str  string
}

func (e *badStringError) String() string { return fmt.Sprintf("%s %q", e.what, e.str) }

func flattenParams(fullParams map[string][]string) map[string]string {
    params := map[string]string{}
    for name, lst := range fullParams {
        if len(lst) > 0 {
            params[name] = lst[0]
        }
    }
    return params
}

func newRequest(hr *http.Request, hc http.ResponseWriter) *Request {

    remoteAddrIP, remotePort := hr.RemoteAddr, 0
    remoteAddr, _ := net.ResolveTCPAddr("tcp", hr.RemoteAddr)
    if remoteAddr != nil {
        remoteAddrIP = remoteAddr.IP.String()
        remotePort = remoteAddr.Port
    }

    req := Request{
        Method:     hr.Method,
        URL:        hr.URL,
        Proto:      hr.Proto,
        ProtoMajor: hr.ProtoMajor,
        ProtoMinor: hr.ProtoMinor,
        Headers:    hr.Header,
        Body:       hr.Body,
        Close:      hr.Close,
        Host:       hr.Host,
        Referer:    hr.Referer(),
        UserAgent:  hr.UserAgent(),
        FullParams: hr.Form,
        Cookie:     hr.Cookies(),
        RemoteAddr: remoteAddrIP,
        RemotePort: remotePort,
    }
    return &req
}

func newRequestCgi(headers http.Header, body io.Reader) *Request {
    var httpheader = make(http.Header)
    for header, value := range headers {
        if strings.HasPrefix(header, "Http_") {
            newHeader := header[5:]
            newHeader = strings.Replace(newHeader, "_", "-", -1)
            newHeader = http.CanonicalHeaderKey(newHeader)
            httpheader[newHeader] = value
        }
    }

    host := httpheader.Get("Host")
    method := headers.Get("REQUEST_METHOD")
    path := headers.Get("REQUEST_URI")
    port := headers.Get("SERVER_PORT")
    proto := headers.Get("SERVER_PROTOCOL")
    rawurl := "http://" + host + ":" + port + path
    url_, _ := url.Parse(rawurl)
    useragent := headers.Get("USER_AGENT")
    remoteAddr := headers.Get("REMOTE_ADDR")
    remotePort, _ := strconv.Atoi(headers.Get("REMOTE_PORT"))

    if method == "POST" {
        if ctype, ok := headers["CONTENT_TYPE"]; ok {
            httpheader["Content-Type"] = ctype
        }

        if clength, ok := headers["CONTENT_LENGTH"]; ok {
            httpheader["Content-Length"] = clength
        }
    }

    //read the cookies
    cookies := readCookies(httpheader)

    req := Request{
        Method:     method,
        RawURL:     rawurl,
        URL:        url_,
        Proto:      proto,
        Host:       host,
        UserAgent:  useragent,
        Body:       body,
        Headers:    httpheader,
        RemoteAddr: remoteAddr,
        RemotePort: remotePort,
        Cookie:     cookies,
    }

    return &req
}

func parseForm(m map[string][]string, query string) (err os.Error) {
    for _, kv := range strings.Split(query, "&") {
        kvPair := strings.SplitN(kv, "=", 2)

        var key, value string
        var e os.Error
        key, e = url.QueryUnescape(kvPair[0])
        if e == nil && len(kvPair) > 1 {
            value, e = url.QueryUnescape(kvPair[1])
        }
        if e != nil {
            err = e
        }

        vec, ok := m[key]
        if !ok {
            vec = []string{}
        }
        m[key] = append(vec, value)
    }

    return
}

// ParseForm parses the request body as a form for POST requests, or the raw query for GET requests.
// It is idempotent.
func (r *Request) parseParams() (err os.Error) {
    if r.Params != nil {
        return
    }
    r.FullParams = make(map[string][]string)
    queryParams := r.URL.RawQuery
    var bodyParams string
    switch r.Method {
    case "POST":
        if r.Body == nil {
            return os.NewError("missing form body")
        }

        ct := r.Headers.Get("Content-Type")
        switch strings.SplitN(ct, ";", 2)[0] {
        case "text/plain", "application/x-www-form-urlencoded", "":
            var b []byte
            if b, err = ioutil.ReadAll(r.Body); err != nil {
                return err
            }
            bodyParams = string(b)
        case "application/json":
            //if we get JSON, do the best we can to convert it to a map[string]string
            //we make the body available as r.ParamData
            var b []byte
            if b, err = ioutil.ReadAll(r.Body); err != nil {
                return err
            }
            r.ParamData = b
            r.Params = map[string]string{}
            json.Unmarshal(b, r.Params)
        case "multipart/form-data":
            _, params := mime.ParseMediaType(ct)
            boundary, ok := params["boundary"]
            if !ok {
                return os.NewError("Missing Boundary")
            }

            reader := multipart.NewReader(r.Body, boundary)
            r.Files = make(map[string]filedata)
            for {
                part, err := reader.NextPart()
                if part == nil && err == os.EOF {
                    break
                }

                if err != nil {
                    return err
                }

                //read the data
                data, _ := ioutil.ReadAll(part)
                //check for the 'filename' param
                v := part.Header.Get("Content-Disposition")
                if v == "" {
                    continue
                }
                name := part.FormName()
                d, params := mime.ParseMediaType(v)
                if d != "form-data" {
                    continue
                }
                if params["filename"] != "" {
                    r.Files[name] = filedata{params["filename"], data}
                } else {
                    var params []string = r.FullParams[name]
                    params = append(params, string(data))
                    r.FullParams[name] = params
                }

            }
        default:
            return &badStringError{"unknown Content-Type", ct}
        }
    }

    if queryParams != "" {
        err = parseForm(r.FullParams, queryParams)
        if err != nil {
            return err
        }
    }

    if bodyParams != "" {
        err = parseForm(r.FullParams, bodyParams)
        if err != nil {
            return err
        }
    }

    r.Params = flattenParams(r.FullParams)
    return nil
}

func (r *Request) HasFile(name string) bool {
    if r.Files == nil || len(r.Files) == 0 {
        return false
    }
    _, ok := r.Files[name]
    return ok
}

func writeTo(s string, val reflect.Value) os.Error {
    switch v := val; v.Kind() {
    // if we're writing to an interace value, just set the byte data
    // TODO: should we support writing to a pointer?
    case reflect.Interface:
        v.Set(reflect.ValueOf(s))
    case reflect.Bool:
        if strings.ToLower(s) == "false" || s == "0" {
            v.SetBool(false)
        } else {
            v.SetBool(true)
        }
    case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
        i, err := strconv.Atoi64(s)
        if err != nil {
            return err
        }
        v.SetInt(i)
    case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
        ui, err := strconv.Atoui64(s)
        if err != nil {
            return err
        }
        v.SetUint(ui)
    case reflect.Float32, reflect.Float64:
        f, err := strconv.Atof64(s)
        if err != nil {
            return err
        }
        v.SetFloat(f)

    case reflect.String:
        v.SetString(s)
    case reflect.Slice:
        typ := v.Type()
        if typ.Elem().Kind() == reflect.Uint || typ.Elem().Kind() == reflect.Uint8 || typ.Elem().Kind() == reflect.Uint16 || typ.Elem().Kind() == reflect.Uint32 || typ.Elem().Kind() == reflect.Uint64 || typ.Elem().Kind() == reflect.Uintptr {
            v.Set(reflect.ValueOf([]byte(s)))
        }
    }
    return nil
}

// matchName returns true if key should be written to a field named name.
func matchName(key, name string) bool {
    return strings.ToLower(key) == strings.ToLower(name)
}

func (r *Request) writeToContainer(val reflect.Value) os.Error {
    switch v := val; v.Kind() {
    case reflect.Ptr:
        return r.writeToContainer(reflect.Indirect(v))
    case reflect.Interface:
        return r.writeToContainer(v.Elem())
    case reflect.Map:
        if v.Type().Key().Kind() != reflect.String {
            return os.NewError("Invalid map type")
        }
        elemtype := v.Type().Elem()
        for pk, pv := range r.Params {
            mk := reflect.ValueOf(pk)
            mv := reflect.Zero(elemtype)
            writeTo(pv, mv)
            v.SetMapIndex(mk, mv)
        }
    case reflect.Struct:
        for pk, pv := range r.Params {
            //try case sensitive match
            field := v.FieldByName(pk)
            if field.IsValid() {
                writeTo(pv, field)
            }

            //try case insensitive matching
            field = v.FieldByNameFunc(func(s string) bool { return matchName(pk, s) })
            if field.IsValid() {
                writeTo(pv, field)
            }

        }
    default:
        return os.NewError("Invalid container type")
    }
    return nil
}

func (r *Request) UnmarshalParams(val interface{}) os.Error {
    if strings.HasPrefix(r.Headers.Get("Content-Type"), "application/json") {
        return json.Unmarshal(r.ParamData, val)
    } else {
        err := r.writeToContainer(reflect.ValueOf(val))
        if err != nil {
            return err
        }
    }

    return nil
}