ducky/devices

Paddy 2016-01-02 Parent:a700ede02f91

20:ed1b5ba69551 Go to Latest

ducky/devices/vendor/code.secondbit.org/pqarrays.hg/lexer.go

Add updating devices to apiv1. We needed a way to be able to update devices after they were created. This is supported in the devices package, we just needed to expose it using apiv1 endpoints. In doing so, it became apparent that allowing users to change the Owner of their Devices wasn't properly thought through, and pending a reason to use it, I'm just removing it. The biggest issue came when trying to return usable error messages; we couldn't distinguish between "you don't own the device you're trying to update" and "you're not allowed to change the owner of the device". I also couldn't figure out _who should be able to_ change the owner of the device, which is generally an indication that I'm building a feature before I have a use case for it. To support this change, the apiv1.DeviceChange type needed its Owner property removed. I also needed to add deviceFromAPI and devicesFromAPI helpers to return devices.Device types from apiv1.Device types. There's now a new validateDeviceUpdate helper that checks to ensure that a device update request is valid and the user has the appropriate permissions. The createRequest type now accepts a slice of Devices, not a slice of DeviceChanges, because we want to pass the Owner in. A new updateRequest type is created, which accepts a DeviceChange to apply. A new handleUpdateDevice handler is created, which is assigned to the endpoint for PATCH requests against a device ID. It checks that the user is logged in, the Device they're trying to update exists, and that it's a valid update. If all of that is true, the device is updated and the updated device is returned. Finally, we had to add two new scopes to support new functionality: ScopeUpdateOtherUserDevices allows a user to update other user's devices, and ScopeUpdateLastSeen allows a user to update the LastSeen property of a device. Pending some better error messages, this should be a full implementation of updating a device, which leaves only the deletion endpoint to deal with.

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1 package pqarrays
2
3 import (
4 "fmt"
5 "strings"
6 "unicode"
7 "unicode/utf8"
8 )
9
10 const (
11 eof = -1
12 leftDelim = "{"
13 rightDelim = "}"
14 separator = ','
15 )
16
17 type tokenType int
18
19 const (
20 tokenError tokenType = iota
21 tokenWhitespace
22 tokenArrayStart
23 tokenString
24 tokenNull
25 tokenSeparator
26 tokenArrayEnd
27 tokenEOF
28 )
29
30 func (t tokenType) String() string {
31 switch t {
32 case tokenError:
33 return "error"
34 case tokenWhitespace:
35 return "whitespace"
36 case tokenArrayStart:
37 return "array start"
38 case tokenString:
39 return "string"
40 case tokenNull:
41 return "null"
42 case tokenSeparator:
43 return "separator"
44 case tokenArrayEnd:
45 return "array end"
46 case tokenEOF:
47 return "eof"
48 default:
49 return "unknown token"
50 }
51 }
52
53 type stateFunc func(*lexer) stateFunc
54
55 type lexer struct {
56 tokens chan token
57 input string
58 start int
59 pos int
60 omitted []int
61 width int
62 state stateFunc
63 arrayDepth int
64 }
65
66 type token struct {
67 typ tokenType
68 val string
69 }
70
71 func lex(input string) *lexer {
72 l := &lexer{
73 input: input,
74 tokens: make(chan token),
75 }
76 go l.run()
77 return l
78 }
79
80 func (l *lexer) nextToken() token {
81 return <-l.tokens
82 }
83
84 func (l *lexer) run() {
85 for l.state = lexStart; l.state != nil; { // TODO(paddy): default state
86 l.state = l.state(l)
87 }
88 }
89
90 func (l *lexer) emit(t tokenType) {
91 var val string
92 if len(l.omitted) < 1 {
93 val = l.input[l.start:l.pos]
94 } else {
95 start := l.start
96 for _, pos := range l.omitted {
97 val += l.input[start:pos]
98 start = pos + 1
99 }
100 if l.pos > start {
101 val += l.input[start:l.pos]
102 }
103 }
104 l.tokens <- token{typ: t, val: val}
105 l.start = l.pos
106 l.omitted = l.omitted[0:0]
107 }
108
109 func (l *lexer) next() rune {
110 if l.pos >= len(l.input) {
111 l.width = 0
112 return eof
113 }
114 var r rune
115 r, l.width = utf8.DecodeRuneInString(l.input[l.pos:])
116 l.pos += l.width
117 return r
118 }
119
120 func (l *lexer) omit() {
121 l.omitted = append(l.omitted, l.pos-1)
122 }
123
124 func (l *lexer) ignore() {
125 l.start = l.pos
126 }
127
128 func (l *lexer) backup() {
129 l.pos -= l.width
130 }
131
132 func (l *lexer) peek() rune {
133 r := l.next()
134 l.backup()
135 return r
136 }
137
138 func (l *lexer) accept(valid string) bool {
139 if strings.IndexRune(valid, l.next()) >= 0 {
140 return true
141 }
142 l.backup()
143 return false
144 }
145
146 func (l *lexer) acceptRun(valid string) {
147 for strings.IndexRune(valid, l.next()) >= 0 {
148 }
149 l.backup()
150 }
151
152 func (l *lexer) errorf(format string, args ...interface{}) stateFunc {
153 l.tokens <- token{tokenError, fmt.Sprintf(format, args...)}
154 return nil
155 }
156
157 func (l *lexer) consumeWhitespace() {
158 for unicode.IsSpace(l.peek()) {
159 l.next()
160 }
161 if l.start > l.pos {
162 l.emit(tokenWhitespace)
163 }
164 }
165
166 func lexStart(l *lexer) stateFunc {
167 l.consumeWhitespace()
168 return lexArrayStart
169 }
170
171 func lexArrayStart(l *lexer) stateFunc {
172 if strings.HasPrefix(l.input[l.pos:], leftDelim) {
173 return lexLeftDelim
174 }
175 return l.errorf("expected array to start before %s", l.input[l.pos:])
176 }
177
178 func lexLeftDelim(l *lexer) stateFunc {
179 l.pos += len(leftDelim)
180 l.emit(tokenArrayStart)
181 l.arrayDepth += 1
182 return lexItem
183 }
184
185 func lexRightDelim(l *lexer) stateFunc {
186 l.pos += len(rightDelim)
187 l.emit(tokenArrayEnd)
188 l.arrayDepth -= 1
189 return lexSeparator
190 }
191
192 func lexItem(l *lexer) stateFunc {
193 l.consumeWhitespace()
194 if strings.HasPrefix(l.input[l.pos:], rightDelim) {
195 return lexRightDelim
196 }
197 if strings.HasPrefix(l.input[l.pos:], leftDelim) {
198 return lexLeftDelim
199 }
200 switch r := l.peek(); {
201 case r == eof:
202 return l.errorf("unclosed array")
203 case r == separator:
204 return l.errorf("empty item in array")
205 case unicode.IsSpace(r):
206 l.consumeWhitespace()
207 return lexItem
208 case r == '"':
209 return lexQuotedString
210 default:
211 return lexString
212 }
213 }
214
215 func lexQuotedString(l *lexer) stateFunc {
216 l.next()
217 l.ignore() // ignore the open quote
218 for {
219 switch r := l.next(); {
220 case r == eof:
221 return l.errorf("unclosed quoted string")
222 case r == '"':
223 l.backup()
224 l.emit(tokenString)
225 l.next()
226 l.ignore()
227 return lexSeparator
228 case r == '\\':
229 // omit the \ itself
230 l.omit()
231 // always skip over the character following a \
232 l.next()
233 if r == eof {
234 return l.errorf("unclosed quoted string")
235 }
236 }
237 }
238 }
239
240 func lexString(l *lexer) stateFunc {
241 for {
242 if strings.HasPrefix(l.input[l.pos:], leftDelim) {
243 return l.errorf(leftDelim + " in unquoted string")
244 }
245 if strings.HasPrefix(l.input[l.pos:], rightDelim) {
246 if l.pos <= l.start {
247 return l.errorf(rightDelim + " in unquoted string")
248 }
249 if string(l.input[l.start:l.pos]) == "NULL" {
250 l.emit(tokenNull)
251 } else {
252 l.emit(tokenString)
253 }
254 return lexRightDelim
255 }
256 switch r := l.next(); {
257 case r == eof:
258 return l.errorf("eof while parsing string")
259 case r == '"':
260 return l.errorf("\" in unquoted string")
261 case unicode.IsSpace(r):
262 return l.errorf("unquoted empty string")
263 case r == '\\':
264 return l.errorf("\\ in unquoted string")
265 case r == separator:
266 l.backup()
267 if l.pos <= l.start {
268 return l.errorf("unquoted empty string")
269 }
270 if string(l.input[l.start:l.pos]) == "NULL" {
271 l.emit(tokenNull)
272 } else {
273 l.emit(tokenString)
274 }
275 return lexSeparator
276 }
277 }
278 }
279
280 func lexSeparator(l *lexer) stateFunc {
281 if strings.HasPrefix(l.input[l.pos:], rightDelim) {
282 return lexRightDelim
283 }
284 r := l.next()
285 if r == separator {
286 l.emit(tokenSeparator)
287 return lexItem
288 } else if r == eof {
289 if l.arrayDepth > 0 {
290 return l.errorf("unclosed array")
291 }
292 l.emit(tokenEOF)
293 return nil
294 } else {
295 l.backup()
296 return l.errorf("expected %s, none found before %s\n", separator, l.input[l.pos:])
297 }
298 }