| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Package url parses URLs and implements query escaping. |
| package url |
| |
| // See RFC 3986. This package generally follows RFC 3986, except where |
| // it deviates for compatibility reasons. When sending changes, first |
| // search old issues for history on decisions. Unit tests should also |
| // contain references to issue numbers with details. |
| |
| import ( |
| "errors" |
| "fmt" |
| "sort" |
| "strconv" |
| "strings" |
| ) |
| |
| // Error reports an error and the operation and URL that caused it. |
| type Error struct { |
| Op string |
| URL string |
| Err error |
| } |
| |
| func (e *Error) Unwrap() error { return e.Err } |
| func (e *Error) Error() string { return fmt.Sprintf("%s %q: %s", e.Op, e.URL, e.Err) } |
| |
| func (e *Error) Timeout() bool { |
| t, ok := e.Err.(interface { |
| Timeout() bool |
| }) |
| return ok && t.Timeout() |
| } |
| |
| func (e *Error) Temporary() bool { |
| t, ok := e.Err.(interface { |
| Temporary() bool |
| }) |
| return ok && t.Temporary() |
| } |
| |
| const upperhex = "0123456789ABCDEF" |
| |
| func ishex(c byte) bool { |
| switch { |
| case '0' <= c && c <= '9': |
| return true |
| case 'a' <= c && c <= 'f': |
| return true |
| case 'A' <= c && c <= 'F': |
| return true |
| } |
| return false |
| } |
| |
| func unhex(c byte) byte { |
| switch { |
| case '0' <= c && c <= '9': |
| return c - '0' |
| case 'a' <= c && c <= 'f': |
| return c - 'a' + 10 |
| case 'A' <= c && c <= 'F': |
| return c - 'A' + 10 |
| } |
| return 0 |
| } |
| |
| type encoding int |
| |
| const ( |
| encodePath encoding = 1 + iota |
| encodePathSegment |
| encodeHost |
| encodeZone |
| encodeUserPassword |
| encodeQueryComponent |
| encodeFragment |
| ) |
| |
| type EscapeError string |
| |
| func (e EscapeError) Error() string { |
| return "invalid URL escape " + strconv.Quote(string(e)) |
| } |
| |
| type InvalidHostError string |
| |
| func (e InvalidHostError) Error() string { |
| return "invalid character " + strconv.Quote(string(e)) + " in host name" |
| } |
| |
| // Return true if the specified character should be escaped when |
| // appearing in a URL string, according to RFC 3986. |
| // |
| // Please be informed that for now shouldEscape does not check all |
| // reserved characters correctly. See golang.org/issue/5684. |
| func shouldEscape(c byte, mode encoding) bool { |
| // §2.3 Unreserved characters (alphanum) |
| if 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z' || '0' <= c && c <= '9' { |
| return false |
| } |
| |
| if mode == encodeHost || mode == encodeZone { |
| // §3.2.2 Host allows |
| // sub-delims = "!" / "$" / "&" / "'" / "(" / ")" / "*" / "+" / "," / ";" / "=" |
| // as part of reg-name. |
| // We add : because we include :port as part of host. |
| // We add [ ] because we include [ipv6]:port as part of host. |
| // We add < > because they're the only characters left that |
| // we could possibly allow, and Parse will reject them if we |
| // escape them (because hosts can't use %-encoding for |
| // ASCII bytes). |
| switch c { |
| case '!', '$', '&', '\'', '(', ')', '*', '+', ',', ';', '=', ':', '[', ']', '<', '>', '"': |
| return false |
| } |
| } |
| |
| switch c { |
| case '-', '_', '.', '~': // §2.3 Unreserved characters (mark) |
| return false |
| |
| case '$', '&', '+', ',', '/', ':', ';', '=', '?', '@': // §2.2 Reserved characters (reserved) |
| // Different sections of the URL allow a few of |
| // the reserved characters to appear unescaped. |
| switch mode { |
| case encodePath: // §3.3 |
| // The RFC allows : @ & = + $ but saves / ; , for assigning |
| // meaning to individual path segments. This package |
| // only manipulates the path as a whole, so we allow those |
| // last three as well. That leaves only ? to escape. |
| return c == '?' |
| |
| case encodePathSegment: // §3.3 |
| // The RFC allows : @ & = + $ but saves / ; , for assigning |
| // meaning to individual path segments. |
| return c == '/' || c == ';' || c == ',' || c == '?' |
| |
| case encodeUserPassword: // §3.2.1 |
| // The RFC allows ';', ':', '&', '=', '+', '$', and ',' in |
| // userinfo, so we must escape only '@', '/', and '?'. |
| // The parsing of userinfo treats ':' as special so we must escape |
| // that too. |
| return c == '@' || c == '/' || c == '?' || c == ':' |
| |
| case encodeQueryComponent: // §3.4 |
| // The RFC reserves (so we must escape) everything. |
| return true |
| |
| case encodeFragment: // §4.1 |
| // The RFC text is silent but the grammar allows |
| // everything, so escape nothing. |
| return false |
| } |
| } |
| |
| if mode == encodeFragment { |
| // RFC 3986 §2.2 allows not escaping sub-delims. A subset of sub-delims are |
| // included in reserved from RFC 2396 §2.2. The remaining sub-delims do not |
| // need to be escaped. To minimize potential breakage, we apply two restrictions: |
| // (1) we always escape sub-delims outside of the fragment, and (2) we always |
| // escape single quote to avoid breaking callers that had previously assumed that |
| // single quotes would be escaped. See issue #19917. |
| switch c { |
| case '!', '(', ')', '*': |
| return false |
| } |
| } |
| |
| // Everything else must be escaped. |
| return true |
| } |
| |
| // QueryUnescape does the inverse transformation of QueryEscape, |
| // converting each 3-byte encoded substring of the form "%AB" into the |
| // hex-decoded byte 0xAB. |
| // It returns an error if any % is not followed by two hexadecimal |
| // digits. |
| func QueryUnescape(s string) (string, error) { |
| return unescape(s, encodeQueryComponent) |
| } |
| |
| // PathUnescape does the inverse transformation of PathEscape, |
| // converting each 3-byte encoded substring of the form "%AB" into the |
| // hex-decoded byte 0xAB. It returns an error if any % is not followed |
| // by two hexadecimal digits. |
| // |
| // PathUnescape is identical to QueryUnescape except that it does not |
| // unescape '+' to ' ' (space). |
| func PathUnescape(s string) (string, error) { |
| return unescape(s, encodePathSegment) |
| } |
| |
| // unescape unescapes a string; the mode specifies |
| // which section of the URL string is being unescaped. |
| func unescape(s string, mode encoding) (string, error) { |
| // Count %, check that they're well-formed. |
| n := 0 |
| hasPlus := false |
| for i := 0; i < len(s); { |
| switch s[i] { |
| case '%': |
| n++ |
| if i+2 >= len(s) || !ishex(s[i+1]) || !ishex(s[i+2]) { |
| s = s[i:] |
| if len(s) > 3 { |
| s = s[:3] |
| } |
| return "", EscapeError(s) |
| } |
| // Per https://tools.ietf.org/html/rfc3986#page-21 |
| // in the host component %-encoding can only be used |
| // for non-ASCII bytes. |
| // But https://tools.ietf.org/html/rfc6874#section-2 |
| // introduces %25 being allowed to escape a percent sign |
| // in IPv6 scoped-address literals. Yay. |
| if mode == encodeHost && unhex(s[i+1]) < 8 && s[i:i+3] != "%25" { |
| return "", EscapeError(s[i : i+3]) |
| } |
| if mode == encodeZone { |
| // RFC 6874 says basically "anything goes" for zone identifiers |
| // and that even non-ASCII can be redundantly escaped, |
| // but it seems prudent to restrict %-escaped bytes here to those |
| // that are valid host name bytes in their unescaped form. |
| // That is, you can use escaping in the zone identifier but not |
| // to introduce bytes you couldn't just write directly. |
| // But Windows puts spaces here! Yay. |
| v := unhex(s[i+1])<<4 | unhex(s[i+2]) |
| if s[i:i+3] != "%25" && v != ' ' && shouldEscape(v, encodeHost) { |
| return "", EscapeError(s[i : i+3]) |
| } |
| } |
| i += 3 |
| case '+': |
| hasPlus = mode == encodeQueryComponent |
| i++ |
| default: |
| if (mode == encodeHost || mode == encodeZone) && s[i] < 0x80 && shouldEscape(s[i], mode) { |
| return "", InvalidHostError(s[i : i+1]) |
| } |
| i++ |
| } |
| } |
| |
| if n == 0 && !hasPlus { |
| return s, nil |
| } |
| |
| var t strings.Builder |
| t.Grow(len(s) - 2*n) |
| for i := 0; i < len(s); i++ { |
| switch s[i] { |
| case '%': |
| t.WriteByte(unhex(s[i+1])<<4 | unhex(s[i+2])) |
| i += 2 |
| case '+': |
| if mode == encodeQueryComponent { |
| t.WriteByte(' ') |
| } else { |
| t.WriteByte('+') |
| } |
| default: |
| t.WriteByte(s[i]) |
| } |
| } |
| return t.String(), nil |
| } |
| |
| // QueryEscape escapes the string so it can be safely placed |
| // inside a URL query. |
| func QueryEscape(s string) string { |
| return escape(s, encodeQueryComponent) |
| } |
| |
| // PathEscape escapes the string so it can be safely placed inside a URL path segment, |
| // replacing special characters (including /) with %XX sequences as needed. |
| func PathEscape(s string) string { |
| return escape(s, encodePathSegment) |
| } |
| |
| func escape(s string, mode encoding) string { |
| spaceCount, hexCount := 0, 0 |
| for i := 0; i < len(s); i++ { |
| c := s[i] |
| if shouldEscape(c, mode) { |
| if c == ' ' && mode == encodeQueryComponent { |
| spaceCount++ |
| } else { |
| hexCount++ |
| } |
| } |
| } |
| |
| if spaceCount == 0 && hexCount == 0 { |
| return s |
| } |
| |
| var buf [64]byte |
| var t []byte |
| |
| required := len(s) + 2*hexCount |
| if required <= len(buf) { |
| t = buf[:required] |
| } else { |
| t = make([]byte, required) |
| } |
| |
| if hexCount == 0 { |
| copy(t, s) |
| for i := 0; i < len(s); i++ { |
| if s[i] == ' ' { |
| t[i] = '+' |
| } |
| } |
| return string(t) |
| } |
| |
| j := 0 |
| for i := 0; i < len(s); i++ { |
| switch c := s[i]; { |
| case c == ' ' && mode == encodeQueryComponent: |
| t[j] = '+' |
| j++ |
| case shouldEscape(c, mode): |
| t[j] = '%' |
| t[j+1] = upperhex[c>>4] |
| t[j+2] = upperhex[c&15] |
| j += 3 |
| default: |
| t[j] = s[i] |
| j++ |
| } |
| } |
| return string(t) |
| } |
| |
| // A URL represents a parsed URL (technically, a URI reference). |
| // |
| // The general form represented is: |
| // |
| // [scheme:][//[userinfo@]host][/]path[?query][#fragment] |
| // |
| // URLs that do not start with a slash after the scheme are interpreted as: |
| // |
| // scheme:opaque[?query][#fragment] |
| // |
| // Note that the Path field is stored in decoded form: /%47%6f%2f becomes /Go/. |
| // A consequence is that it is impossible to tell which slashes in the Path were |
| // slashes in the raw URL and which were %2f. This distinction is rarely important, |
| // but when it is, the code should use RawPath, an optional field which only gets |
| // set if the default encoding is different from Path. |
| // |
| // URL's String method uses the EscapedPath method to obtain the path. See the |
| // EscapedPath method for more details. |
| type URL struct { |
| Scheme string |
| Opaque string // encoded opaque data |
| User *Userinfo // username and password information |
| Host string // host or host:port |
| Path string // path (relative paths may omit leading slash) |
| RawPath string // encoded path hint (see EscapedPath method) |
| ForceQuery bool // append a query ('?') even if RawQuery is empty |
| RawQuery string // encoded query values, without '?' |
| Fragment string // fragment for references, without '#' |
| } |
| |
| // User returns a Userinfo containing the provided username |
| // and no password set. |
| func User(username string) *Userinfo { |
| return &Userinfo{username, "", false} |
| } |
| |
| // UserPassword returns a Userinfo containing the provided username |
| // and password. |
| // |
| // This functionality should only be used with legacy web sites. |
| // RFC 2396 warns that interpreting Userinfo this way |
| // ``is NOT RECOMMENDED, because the passing of authentication |
| // information in clear text (such as URI) has proven to be a |
| // security risk in almost every case where it has been used.'' |
| func UserPassword(username, password string) *Userinfo { |
| return &Userinfo{username, password, true} |
| } |
| |
| // The Userinfo type is an immutable encapsulation of username and |
| // password details for a URL. An existing Userinfo value is guaranteed |
| // to have a username set (potentially empty, as allowed by RFC 2396), |
| // and optionally a password. |
| type Userinfo struct { |
| username string |
| password string |
| passwordSet bool |
| } |
| |
| // Username returns the username. |
| func (u *Userinfo) Username() string { |
| if u == nil { |
| return "" |
| } |
| return u.username |
| } |
| |
| // Password returns the password in case it is set, and whether it is set. |
| func (u *Userinfo) Password() (string, bool) { |
| if u == nil { |
| return "", false |
| } |
| return u.password, u.passwordSet |
| } |
| |
| // String returns the encoded userinfo information in the standard form |
| // of "username[:password]". |
| func (u *Userinfo) String() string { |
| if u == nil { |
| return "" |
| } |
| s := escape(u.username, encodeUserPassword) |
| if u.passwordSet { |
| s += ":" + escape(u.password, encodeUserPassword) |
| } |
| return s |
| } |
| |
| // Maybe rawurl is of the form scheme:path. |
| // (Scheme must be [a-zA-Z][a-zA-Z0-9+-.]*) |
| // If so, return scheme, path; else return "", rawurl. |
| func getscheme(rawurl string) (scheme, path string, err error) { |
| for i := 0; i < len(rawurl); i++ { |
| c := rawurl[i] |
| switch { |
| case 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z': |
| // do nothing |
| case '0' <= c && c <= '9' || c == '+' || c == '-' || c == '.': |
| if i == 0 { |
| return "", rawurl, nil |
| } |
| case c == ':': |
| if i == 0 { |
| return "", "", errors.New("missing protocol scheme") |
| } |
| return rawurl[:i], rawurl[i+1:], nil |
| default: |
| // we have encountered an invalid character, |
| // so there is no valid scheme |
| return "", rawurl, nil |
| } |
| } |
| return "", rawurl, nil |
| } |
| |
| // split slices s into two substrings separated by the first occurrence of |
| // sep. If cutc is true then sep is included with the second substring. |
| // If sep does not occur in s then s and the empty string is returned. |
| func split(s string, sep byte, cutc bool) (string, string) { |
| i := strings.IndexByte(s, sep) |
| if i < 0 { |
| return s, "" |
| } |
| if cutc { |
| return s[:i], s[i+1:] |
| } |
| return s[:i], s[i:] |
| } |
| |
| // Parse parses rawurl into a URL structure. |
| // |
| // The rawurl may be relative (a path, without a host) or absolute |
| // (starting with a scheme). Trying to parse a hostname and path |
| // without a scheme is invalid but may not necessarily return an |
| // error, due to parsing ambiguities. |
| func Parse(rawurl string) (*URL, error) { |
| // Cut off #frag |
| u, frag := split(rawurl, '#', true) |
| url, err := parse(u, false) |
| if err != nil { |
| return nil, &Error{"parse", u, err} |
| } |
| if frag == "" { |
| return url, nil |
| } |
| if url.Fragment, err = unescape(frag, encodeFragment); err != nil { |
| return nil, &Error{"parse", rawurl, err} |
| } |
| return url, nil |
| } |
| |
| // ParseRequestURI parses rawurl into a URL structure. It assumes that |
| // rawurl was received in an HTTP request, so the rawurl is interpreted |
| // only as an absolute URI or an absolute path. |
| // The string rawurl is assumed not to have a #fragment suffix. |
| // (Web browsers strip #fragment before sending the URL to a web server.) |
| func ParseRequestURI(rawurl string) (*URL, error) { |
| url, err := parse(rawurl, true) |
| if err != nil { |
| return nil, &Error{"parse", rawurl, err} |
| } |
| return url, nil |
| } |
| |
| // parse parses a URL from a string in one of two contexts. If |
| // viaRequest is true, the URL is assumed to have arrived via an HTTP request, |
| // in which case only absolute URLs or path-absolute relative URLs are allowed. |
| // If viaRequest is false, all forms of relative URLs are allowed. |
| func parse(rawurl string, viaRequest bool) (*URL, error) { |
| var rest string |
| var err error |
| |
| if stringContainsCTLByte(rawurl) { |
| return nil, errors.New("net/url: invalid control character in URL") |
| } |
| |
| if rawurl == "" && viaRequest { |
| return nil, errors.New("empty url") |
| } |
| url := new(URL) |
| |
| if rawurl == "*" { |
| url.Path = "*" |
| return url, nil |
| } |
| |
| // Split off possible leading "http:", "mailto:", etc. |
| // Cannot contain escaped characters. |
| if url.Scheme, rest, err = getscheme(rawurl); err != nil { |
| return nil, err |
| } |
| url.Scheme = strings.ToLower(url.Scheme) |
| |
| if strings.HasSuffix(rest, "?") && strings.Count(rest, "?") == 1 { |
| url.ForceQuery = true |
| rest = rest[:len(rest)-1] |
| } else { |
| rest, url.RawQuery = split(rest, '?', true) |
| } |
| |
| if !strings.HasPrefix(rest, "/") { |
| if url.Scheme != "" { |
| // We consider rootless paths per RFC 3986 as opaque. |
| url.Opaque = rest |
| return url, nil |
| } |
| if viaRequest { |
| return nil, errors.New("invalid URI for request") |
| } |
| |
| // Avoid confusion with malformed schemes, like cache_object:foo/bar. |
| // See golang.org/issue/16822. |
| // |
| // RFC 3986, §3.3: |
| // In addition, a URI reference (Section 4.1) may be a relative-path reference, |
| // in which case the first path segment cannot contain a colon (":") character. |
| colon := strings.Index(rest, ":") |
| slash := strings.Index(rest, "/") |
| if colon >= 0 && (slash < 0 || colon < slash) { |
| // First path segment has colon. Not allowed in relative URL. |
| return nil, errors.New("first path segment in URL cannot contain colon") |
| } |
| } |
| |
| if (url.Scheme != "" || !viaRequest && !strings.HasPrefix(rest, "///")) && strings.HasPrefix(rest, "//") { |
| var authority string |
| authority, rest = split(rest[2:], '/', false) |
| url.User, url.Host, err = parseAuthority(authority) |
| if err != nil { |
| return nil, err |
| } |
| } |
| // Set Path and, optionally, RawPath. |
| // RawPath is a hint of the encoding of Path. We don't want to set it if |
| // the default escaping of Path is equivalent, to help make sure that people |
| // don't rely on it in general. |
| if err := url.setPath(rest); err != nil { |
| return nil, err |
| } |
| return url, nil |
| } |
| |
| func parseAuthority(authority string) (user *Userinfo, host string, err error) { |
| i := strings.LastIndex(authority, "@") |
| if i < 0 { |
| host, err = parseHost(authority) |
| } else { |
| host, err = parseHost(authority[i+1:]) |
| } |
| if err != nil { |
| return nil, "", err |
| } |
| if i < 0 { |
| return nil, host, nil |
| } |
| userinfo := authority[:i] |
| if !validUserinfo(userinfo) { |
| return nil, "", errors.New("net/url: invalid userinfo") |
| } |
| if !strings.Contains(userinfo, ":") { |
| if userinfo, err = unescape(userinfo, encodeUserPassword); err != nil { |
| return nil, "", err |
| } |
| user = User(userinfo) |
| } else { |
| username, password := split(userinfo, ':', true) |
| if username, err = unescape(username, encodeUserPassword); err != nil { |
| return nil, "", err |
| } |
| if password, err = unescape(password, encodeUserPassword); err != nil { |
| return nil, "", err |
| } |
| user = UserPassword(username, password) |
| } |
| return user, host, nil |
| } |
| |
| // parseHost parses host as an authority without user |
| // information. That is, as host[:port]. |
| func parseHost(host string) (string, error) { |
| if strings.HasPrefix(host, "[") { |
| // Parse an IP-Literal in RFC 3986 and RFC 6874. |
| // E.g., "[fe80::1]", "[fe80::1%25en0]", "[fe80::1]:80". |
| i := strings.LastIndex(host, "]") |
| if i < 0 { |
| return "", errors.New("missing ']' in host") |
| } |
| colonPort := host[i+1:] |
| if !validOptionalPort(colonPort) { |
| return "", fmt.Errorf("invalid port %q after host", colonPort) |
| } |
| |
| // RFC 6874 defines that %25 (%-encoded percent) introduces |
| // the zone identifier, and the zone identifier can use basically |
| // any %-encoding it likes. That's different from the host, which |
| // can only %-encode non-ASCII bytes. |
| // We do impose some restrictions on the zone, to avoid stupidity |
| // like newlines. |
| zone := strings.Index(host[:i], "%25") |
| if zone >= 0 { |
| host1, err := unescape(host[:zone], encodeHost) |
| if err != nil { |
| return "", err |
| } |
| host2, err := unescape(host[zone:i], encodeZone) |
| if err != nil { |
| return "", err |
| } |
| host3, err := unescape(host[i:], encodeHost) |
| if err != nil { |
| return "", err |
| } |
| return host1 + host2 + host3, nil |
| } |
| } else if i := strings.LastIndex(host, ":"); i != -1 { |
| colonPort := host[i:] |
| if !validOptionalPort(colonPort) { |
| return "", fmt.Errorf("invalid port %q after host", colonPort) |
| } |
| } |
| |
| var err error |
| if host, err = unescape(host, encodeHost); err != nil { |
| return "", err |
| } |
| return host, nil |
| } |
| |
| // setPath sets the Path and RawPath fields of the URL based on the provided |
| // escaped path p. It maintains the invariant that RawPath is only specified |
| // when it differs from the default encoding of the path. |
| // For example: |
| // - setPath("/foo/bar") will set Path="/foo/bar" and RawPath="" |
| // - setPath("/foo%2fbar") will set Path="/foo/bar" and RawPath="/foo%2fbar" |
| // setPath will return an error only if the provided path contains an invalid |
| // escaping. |
| func (u *URL) setPath(p string) error { |
| path, err := unescape(p, encodePath) |
| if err != nil { |
| return err |
| } |
| u.Path = path |
| if escp := escape(path, encodePath); p == escp { |
| // Default encoding is fine. |
| u.RawPath = "" |
| } else { |
| u.RawPath = p |
| } |
| return nil |
| } |
| |
| // EscapedPath returns the escaped form of u.Path. |
| // In general there are multiple possible escaped forms of any path. |
| // EscapedPath returns u.RawPath when it is a valid escaping of u.Path. |
| // Otherwise EscapedPath ignores u.RawPath and computes an escaped |
| // form on its own. |
| // The String and RequestURI methods use EscapedPath to construct |
| // their results. |
| // In general, code should call EscapedPath instead of |
| // reading u.RawPath directly. |
| func (u *URL) EscapedPath() string { |
| if u.RawPath != "" && validEncodedPath(u.RawPath) { |
| p, err := unescape(u.RawPath, encodePath) |
| if err == nil && p == u.Path { |
| return u.RawPath |
| } |
| } |
| if u.Path == "*" { |
| return "*" // don't escape (Issue 11202) |
| } |
| return escape(u.Path, encodePath) |
| } |
| |
| // validEncodedPath reports whether s is a valid encoded path. |
| // It must not contain any bytes that require escaping during path encoding. |
| func validEncodedPath(s string) bool { |
| for i := 0; i < len(s); i++ { |
| // RFC 3986, Appendix A. |
| // pchar = unreserved / pct-encoded / sub-delims / ":" / "@". |
| // shouldEscape is not quite compliant with the RFC, |
| // so we check the sub-delims ourselves and let |
| // shouldEscape handle the others. |
| switch s[i] { |
| case '!', '$', '&', '\'', '(', ')', '*', '+', ',', ';', '=', ':', '@': |
| // ok |
| case '[', ']': |
| // ok - not specified in RFC 3986 but left alone by modern browsers |
| case '%': |
| // ok - percent encoded, will decode |
| default: |
| if shouldEscape(s[i], encodePath) { |
| return false |
| } |
| } |
| } |
| return true |
| } |
| |
| // validOptionalPort reports whether port is either an empty string |
| // or matches /^:\d*$/ |
| func validOptionalPort(port string) bool { |
| if port == "" { |
| return true |
| } |
| if port[0] != ':' { |
| return false |
| } |
| for _, b := range port[1:] { |
| if b < '0' || b > '9' { |
| return false |
| } |
| } |
| return true |
| } |
| |
| // String reassembles the URL into a valid URL string. |
| // The general form of the result is one of: |
| // |
| // scheme:opaque?query#fragment |
| // scheme://userinfo@host/path?query#fragment |
| // |
| // If u.Opaque is non-empty, String uses the first form; |
| // otherwise it uses the second form. |
| // Any non-ASCII characters in host are escaped. |
| // To obtain the path, String uses u.EscapedPath(). |
| // |
| // In the second form, the following rules apply: |
| // - if u.Scheme is empty, scheme: is omitted. |
| // - if u.User is nil, userinfo@ is omitted. |
| // - if u.Host is empty, host/ is omitted. |
| // - if u.Scheme and u.Host are empty and u.User is nil, |
| // the entire scheme://userinfo@host/ is omitted. |
| // - if u.Host is non-empty and u.Path begins with a /, |
| // the form host/path does not add its own /. |
| // - if u.RawQuery is empty, ?query is omitted. |
| // - if u.Fragment is empty, #fragment is omitted. |
| func (u *URL) String() string { |
| var buf strings.Builder |
| if u.Scheme != "" { |
| buf.WriteString(u.Scheme) |
| buf.WriteByte(':') |
| } |
| if u.Opaque != "" { |
| buf.WriteString(u.Opaque) |
| } else { |
| if u.Scheme != "" || u.Host != "" || u.User != nil { |
| if u.Host != "" || u.Path != "" || u.User != nil { |
| buf.WriteString("//") |
| } |
| if ui := u.User; ui != nil { |
| buf.WriteString(ui.String()) |
| buf.WriteByte('@') |
| } |
| if h := u.Host; h != "" { |
| buf.WriteString(escape(h, encodeHost)) |
| } |
| } |
| path := u.EscapedPath() |
| if path != "" && path[0] != '/' && u.Host != "" { |
| buf.WriteByte('/') |
| } |
| if buf.Len() == 0 { |
| // RFC 3986 §4.2 |
| // A path segment that contains a colon character (e.g., "this:that") |
| // cannot be used as the first segment of a relative-path reference, as |
| // it would be mistaken for a scheme name. Such a segment must be |
| // preceded by a dot-segment (e.g., "./this:that") to make a relative- |
| // path reference. |
| if i := strings.IndexByte(path, ':'); i > -1 && strings.IndexByte(path[:i], '/') == -1 { |
| buf.WriteString("./") |
| } |
| } |
| buf.WriteString(path) |
| } |
| if u.ForceQuery || u.RawQuery != "" { |
| buf.WriteByte('?') |
| buf.WriteString(u.RawQuery) |
| } |
| if u.Fragment != "" { |
| buf.WriteByte('#') |
| buf.WriteString(escape(u.Fragment, encodeFragment)) |
| } |
| return buf.String() |
| } |
| |
| // Values maps a string key to a list of values. |
| // It is typically used for query parameters and form values. |
| // Unlike in the http.Header map, the keys in a Values map |
| // are case-sensitive. |
| type Values map[string][]string |
| |
| // Get gets the first value associated with the given key. |
| // If there are no values associated with the key, Get returns |
| // the empty string. To access multiple values, use the map |
| // directly. |
| func (v Values) Get(key string) string { |
| if v == nil { |
| return "" |
| } |
| vs := v[key] |
| if len(vs) == 0 { |
| return "" |
| } |
| return vs[0] |
| } |
| |
| // Set sets the key to value. It replaces any existing |
| // values. |
| func (v Values) Set(key, value string) { |
| v[key] = []string{value} |
| } |
| |
| // Add adds the value to key. It appends to any existing |
| // values associated with key. |
| func (v Values) Add(key, value string) { |
| v[key] = append(v[key], value) |
| } |
| |
| // Del deletes the values associated with key. |
| func (v Values) Del(key string) { |
| delete(v, key) |
| } |
| |
| // ParseQuery parses the URL-encoded query string and returns |
| // a map listing the values specified for each key. |
| // ParseQuery always returns a non-nil map containing all the |
| // valid query parameters found; err describes the first decoding error |
| // encountered, if any. |
| // |
| // Query is expected to be a list of key=value settings separated by |
| // ampersands or semicolons. A setting without an equals sign is |
| // interpreted as a key set to an empty value. |
| func ParseQuery(query string) (Values, error) { |
| m := make(Values) |
| err := parseQuery(m, query) |
| return m, err |
| } |
| |
| func parseQuery(m Values, query string) (err error) { |
| for query != "" { |
| key := query |
| if i := strings.IndexAny(key, "&;"); i >= 0 { |
| key, query = key[:i], key[i+1:] |
| } else { |
| query = "" |
| } |
| if key == "" { |
| continue |
| } |
| value := "" |
| if i := strings.Index(key, "="); i >= 0 { |
| key, value = key[:i], key[i+1:] |
| } |
| key, err1 := QueryUnescape(key) |
| if err1 != nil { |
| if err == nil { |
| err = err1 |
| } |
| continue |
| } |
| value, err1 = QueryUnescape(value) |
| if err1 != nil { |
| if err == nil { |
| err = err1 |
| } |
| continue |
| } |
| m[key] = append(m[key], value) |
| } |
| return err |
| } |
| |
| // Encode encodes the values into ``URL encoded'' form |
| // ("bar=baz&foo=quux") sorted by key. |
| func (v Values) Encode() string { |
| if v == nil { |
| return "" |
| } |
| var buf strings.Builder |
| keys := make([]string, 0, len(v)) |
| for k := range v { |
| keys = append(keys, k) |
| } |
| sort.Strings(keys) |
| for _, k := range keys { |
| vs := v[k] |
| keyEscaped := QueryEscape(k) |
| for _, v := range vs { |
| if buf.Len() > 0 { |
| buf.WriteByte('&') |
| } |
| buf.WriteString(keyEscaped) |
| buf.WriteByte('=') |
| buf.WriteString(QueryEscape(v)) |
| } |
| } |
| return buf.String() |
| } |
| |
| // resolvePath applies special path segments from refs and applies |
| // them to base, per RFC 3986. |
| func resolvePath(base, ref string) string { |
| var full string |
| if ref == "" { |
| full = base |
| } else if ref[0] != '/' { |
| i := strings.LastIndex(base, "/") |
| full = base[:i+1] + ref |
| } else { |
| full = ref |
| } |
| if full == "" { |
| return "" |
| } |
| src := strings.Split(full, "/") |
| dst := make([]string, 0, len(src)) |
| for _, elem := range src { |
| switch elem { |
| case ".": |
| // drop |
| case "..": |
| if len(dst) > 0 { |
| dst = dst[:len(dst)-1] |
| } |
| default: |
| dst = append(dst, elem) |
| } |
| } |
| if last := src[len(src)-1]; last == "." || last == ".." { |
| // Add final slash to the joined path. |
| dst = append(dst, "") |
| } |
| return "/" + strings.TrimPrefix(strings.Join(dst, "/"), "/") |
| } |
| |
| // IsAbs reports whether the URL is absolute. |
| // Absolute means that it has a non-empty scheme. |
| func (u *URL) IsAbs() bool { |
| return u.Scheme != "" |
| } |
| |
| // Parse parses a URL in the context of the receiver. The provided URL |
| // may be relative or absolute. Parse returns nil, err on parse |
| // failure, otherwise its return value is the same as ResolveReference. |
| func (u *URL) Parse(ref string) (*URL, error) { |
| refurl, err := Parse(ref) |
| if err != nil { |
| return nil, err |
| } |
| return u.ResolveReference(refurl), nil |
| } |
| |
| // ResolveReference resolves a URI reference to an absolute URI from |
| // an absolute base URI u, per RFC 3986 Section 5.2. The URI reference |
| // may be relative or absolute. ResolveReference always returns a new |
| // URL instance, even if the returned URL is identical to either the |
| // base or reference. If ref is an absolute URL, then ResolveReference |
| // ignores base and returns a copy of ref. |
| func (u *URL) ResolveReference(ref *URL) *URL { |
| url := *ref |
| if ref.Scheme == "" { |
| url.Scheme = u.Scheme |
| } |
| if ref.Scheme != "" || ref.Host != "" || ref.User != nil { |
| // The "absoluteURI" or "net_path" cases. |
| // We can ignore the error from setPath since we know we provided a |
| // validly-escaped path. |
| url.setPath(resolvePath(ref.EscapedPath(), "")) |
| return &url |
| } |
| if ref.Opaque != "" { |
| url.User = nil |
| url.Host = "" |
| url.Path = "" |
| return &url |
| } |
| if ref.Path == "" && ref.RawQuery == "" { |
| url.RawQuery = u.RawQuery |
| if ref.Fragment == "" { |
| url.Fragment = u.Fragment |
| } |
| } |
| // The "abs_path" or "rel_path" cases. |
| url.Host = u.Host |
| url.User = u.User |
| url.setPath(resolvePath(u.EscapedPath(), ref.EscapedPath())) |
| return &url |
| } |
| |
| // Query parses RawQuery and returns the corresponding values. |
| // It silently discards malformed value pairs. |
| // To check errors use ParseQuery. |
| func (u *URL) Query() Values { |
| v, _ := ParseQuery(u.RawQuery) |
| return v |
| } |
| |
| // RequestURI returns the encoded path?query or opaque?query |
| // string that would be used in an HTTP request for u. |
| func (u *URL) RequestURI() string { |
| result := u.Opaque |
| if result == "" { |
| result = u.EscapedPath() |
| if result == "" { |
| result = "/" |
| } |
| } else { |
| if strings.HasPrefix(result, "//") { |
| result = u.Scheme + ":" + result |
| } |
| } |
| if u.ForceQuery || u.RawQuery != "" { |
| result += "?" + u.RawQuery |
| } |
| return result |
| } |
| |
| // Hostname returns u.Host, stripping any valid port number if present. |
| // |
| // If the result is enclosed in square brackets, as literal IPv6 addresses are, |
| // the square brackets are removed from the result. |
| func (u *URL) Hostname() string { |
| host, _ := splitHostPort(u.Host) |
| return host |
| } |
| |
| // Port returns the port part of u.Host, without the leading colon. |
| // |
| // If u.Host doesn't contain a valid numeric port, Port returns an empty string. |
| func (u *URL) Port() string { |
| _, port := splitHostPort(u.Host) |
| return port |
| } |
| |
| // splitHostPort separates host and port. If the port is not valid, it returns |
| // the entire input as host, and it doesn't check the validity of the host. |
| // Unlike net.SplitHostPort, but per RFC 3986, it requires ports to be numeric. |
| func splitHostPort(hostport string) (host, port string) { |
| host = hostport |
| |
| colon := strings.LastIndexByte(host, ':') |
| if colon != -1 && validOptionalPort(host[colon:]) { |
| host, port = host[:colon], host[colon+1:] |
| } |
| |
| if strings.HasPrefix(host, "[") && strings.HasSuffix(host, "]") { |
| host = host[1 : len(host)-1] |
| } |
| |
| return |
| } |
| |
| // Marshaling interface implementations. |
| // Would like to implement MarshalText/UnmarshalText but that will change the JSON representation of URLs. |
| |
| func (u *URL) MarshalBinary() (text []byte, err error) { |
| return []byte(u.String()), nil |
| } |
| |
| func (u *URL) UnmarshalBinary(text []byte) error { |
| u1, err := Parse(string(text)) |
| if err != nil { |
| return err |
| } |
| *u = *u1 |
| return nil |
| } |
| |
| // validUserinfo reports whether s is a valid userinfo string per RFC 3986 |
| // Section 3.2.1: |
| // userinfo = *( unreserved / pct-encoded / sub-delims / ":" ) |
| // unreserved = ALPHA / DIGIT / "-" / "." / "_" / "~" |
| // sub-delims = "!" / "$" / "&" / "'" / "(" / ")" |
| // / "*" / "+" / "," / ";" / "=" |
| // |
| // It doesn't validate pct-encoded. The caller does that via func unescape. |
| func validUserinfo(s string) bool { |
| for _, r := range s { |
| if 'A' <= r && r <= 'Z' { |
| continue |
| } |
| if 'a' <= r && r <= 'z' { |
| continue |
| } |
| if '0' <= r && r <= '9' { |
| continue |
| } |
| switch r { |
| case '-', '.', '_', ':', '~', '!', '$', '&', '\'', |
| '(', ')', '*', '+', ',', ';', '=', '%', '@': |
| continue |
| default: |
| return false |
| } |
| } |
| return true |
| } |
| |
| // stringContainsCTLByte reports whether s contains any ASCII control character. |
| func stringContainsCTLByte(s string) bool { |
| for i := 0; i < len(s); i++ { |
| b := s[i] |
| if b < ' ' || b == 0x7f { |
| return true |
| } |
| } |
| return false |
| } |