1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
|
headline: Tutorial
body:
- text: |
GitHub has a JSON API, so let's play with that. This URL gets us the last
5 commits from the jq repo.
- command: "curl 'https://api.github.com/repos/stedolan/jq/commits?per_page=5'"
result: |
[
{
"sha": "d25341478381063d1c76e81b3a52e0592a7c997f",
"commit": {
"author": {
"name": "Stephen Dolan",
"email": "mu@netsoc.tcd.ie",
"date": "2013-06-22T16:30:59Z"
},
"committer": {
"name": "Stephen Dolan",
"email": "mu@netsoc.tcd.ie",
"date": "2013-06-22T16:30:59Z"
},
"message": "Merge pull request #162 from stedolan/utf8-fixes\n\nUtf8 fixes. Closes #161",
"tree": {
"sha": "6ab697a8dfb5a96e124666bf6d6213822599fb40",
"url": "https://api.github.com/repos/stedolan/jq/git/trees/6ab697a8dfb5a96e124666bf6d6213822599fb40"
},
"url": "https://api.github.com/repos/stedolan/jq/git/commits/d25341478381063d1c76e81b3a52e0592a7c997f",
"comment_count": 0
},
"url": "https://api.github.com/repos/stedolan/jq/commits/d25341478381063d1c76e81b3a52e0592a7c997f",
"html_url": "https://github.com/stedolan/jq/commit/d25341478381063d1c76e81b3a52e0592a7c997f",
"comments_url": "https://api.github.com/repos/stedolan/jq/commits/d25341478381063d1c76e81b3a52e0592a7c997f/comments",
"author": {
"login": "stedolan",
...
- text: |
GitHub returns nicely formatted JSON. For servers that don't, it can be
helpful to pipe the response through jq to pretty-print it. The simplest
jq program is the expression `.`, which takes the input and produces it
unchanged as output.
- command: "curl 'https://api.github.com/repos/stedolan/jq/commits?per_page=5' | jq '.'"
result: |
[
{
"sha": "d25341478381063d1c76e81b3a52e0592a7c997f",
"commit": {
"author": {
"name": "Stephen Dolan",
"email": "mu@netsoc.tcd.ie",
"date": "2013-06-22T16:30:59Z"
},
"committer": {
"name": "Stephen Dolan",
"email": "mu@netsoc.tcd.ie",
"date": "2013-06-22T16:30:59Z"
},
"message": "Merge pull request #162 from stedolan/utf8-fixes\n\nUtf8 fixes. Closes #161",
"tree": {
"sha": "6ab697a8dfb5a96e124666bf6d6213822599fb40",
"url": "https://api.github.com/repos/stedolan/jq/git/trees/6ab697a8dfb5a96e124666bf6d6213822599fb40"
},
"url": "https://api.github.com/repos/stedolan/jq/git/commits/d25341478381063d1c76e81b3a52e0592a7c997f",
"comment_count": 0
},
"url": "https://api.github.com/repos/stedolan/jq/commits/d25341478381063d1c76e81b3a52e0592a7c997f",
"html_url": "https://github.com/stedolan/jq/commit/d25341478381063d1c76e81b3a52e0592a7c997f",
"comments_url": "https://api.github.com/repos/stedolan/jq/commits/d25341478381063d1c76e81b3a52e0592a7c997f/comments",
"author": {
"login": "stedolan",
...
- text: |
We can use jq to extract just the first commit.
- command: "curl 'https://api.github.com/repos/stedolan/jq/commits?per_page=5' | jq '.[0]'"
result: |
{
"sha": "d25341478381063d1c76e81b3a52e0592a7c997f",
"commit": {
"author": {
"name": "Stephen Dolan",
"email": "mu@netsoc.tcd.ie",
"date": "2013-06-22T16:30:59Z"
},
"committer": {
"name": "Stephen Dolan",
"email": "mu@netsoc.tcd.ie",
"date": "2013-06-22T16:30:59Z"
},
"message": "Merge pull request #162 from stedolan/utf8-fixes\n\nUtf8 fixes. Closes #161",
"tree": {
"sha": "6ab697a8dfb5a96e124666bf6d6213822599fb40",
"url": "https://api.github.com/repos/stedolan/jq/git/trees/6ab697a8dfb5a96e124666bf6d6213822599fb40"
},
"url": "https://api.github.com/repos/stedolan/jq/git/commits/d25341478381063d1c76e81b3a52e0592a7c997f",
"comment_count": 0
},
"url": "https://api.github.com/repos/stedolan/jq/commits/d25341478381063d1c76e81b3a52e0592a7c997f",
"html_url": "https://github.com/stedolan/jq/commit/d25341478381063d1c76e81b3a52e0592a7c997f",
"comments_url": "https://api.github.com/repos/stedolan/jq/commits/d25341478381063d1c76e81b3a52e0592a7c997f/comments",
"author": {
"login": "stedolan",
"id": 79765,
"avatar_url": "https://avatars.githubusercontent.com/u/79765?v=3",
"gravatar_id": "",
"url": "https://api.github.com/users/stedolan",
"html_url": "https://github.com/stedolan",
"followers_url": "https://api.github.com/users/stedolan/followers",
"following_url": "https://api.github.com/users/stedolan/following{/other_user}",
"gists_url": "https://api.github.com/users/stedolan/gists{/gist_id}",
"starred_url": "https://api.github.com/users/stedolan/starred{/owner}{/repo}",
"subscriptions_url": "https://api.github.com/users/stedolan/subscriptions",
"organizations_url": "https://api.github.com/users/stedolan/orgs",
"repos_url": "https://api.github.com/users/stedolan/repos",
"events_url": "https://api.github.com/users/stedolan/events{/privacy}",
"received_events_url": "https://api.github.com/users/stedolan/received_events",
"type": "User",
"site_admin": false
},
"committer": {
"login": "stedolan",
"id": 79765,
"avatar_url": "https://avatars.githubusercontent.com/u/79765?v=3",
"gravatar_id": "",
"url": "https://api.github.com/users/stedolan",
"html_url": "https://github.com/stedolan",
"followers_url": "https://api.github.com/users/stedolan/followers",
"following_url": "https://api.github.com/users/stedolan/following{/other_user}",
"gists_url": "https://api.github.com/users/stedolan/gists{/gist_id}",
"starred_url": "https://api.github.com/users/stedolan/starred{/owner}{/repo}",
"subscriptions_url": "https://api.github.com/users/stedolan/subscriptions",
"organizations_url": "https://api.github.com/users/stedolan/orgs",
"repos_url": "https://api.github.com/users/stedolan/repos",
"events_url": "https://api.github.com/users/stedolan/events{/privacy}",
"received_events_url": "https://api.github.com/users/stedolan/received_events",
"type": "User",
"site_admin": false
},
"parents": [
{
"sha": "54b9c9bdb225af5d886466d72f47eafc51acb4f7",
"url": "https://api.github.com/repos/stedolan/jq/commits/54b9c9bdb225af5d886466d72f47eafc51acb4f7",
"html_url": "https://github.com/stedolan/jq/commit/54b9c9bdb225af5d886466d72f47eafc51acb4f7"
},
{
"sha": "8b1b503609c161fea4b003a7179b3fbb2dd4345a",
"url": "https://api.github.com/repos/stedolan/jq/commits/8b1b503609c161fea4b003a7179b3fbb2dd4345a",
"html_url": "https://github.com/stedolan/jq/commit/8b1b503609c161fea4b003a7179b3fbb2dd4345a"
}
]
}
- text: |
For the rest of the examples, I'll leave out the `curl` command - it's not
going to change.
There's a lot of info we don't care about there, so we'll restrict it down
to the most interesting fields.
- command: "jq '.[0] | {message: .commit.message, name: .commit.committer.name}'"
result: |
{
"message": "Merge pull request #162 from stedolan/utf8-fixes\n\nUtf8 fixes. Closes #161",
"name": "Stephen Dolan"
}
- text: |
The `|` operator in jq feeds the output of one filter (`.[0]` which gets
the first element of the array in the response) into the input of another
(`{...}` which builds an object out of those fields). You can access
nested attributes, such as `.commit.message`.
Now let's get the rest of the commits.
- command: "jq '.[] | {message: .commit.message, name: .commit.committer.name}'"
result: |
{
"message": "Merge pull request #162 from stedolan/utf8-fixes\n\nUtf8 fixes. Closes #161",
"name": "Stephen Dolan"
}
{
"message": "Reject all overlong UTF8 sequences.",
"name": "Stephen Dolan"
}
{
"message": "Fix various UTF8 parsing bugs.\n\nIn particular, parse bad UTF8 by replacing the broken bits with U+FFFD\nand resychronise correctly after broken sequences.",
"name": "Stephen Dolan"
}
{
"message": "Fix example in manual for `floor`. See #155.",
"name": "Stephen Dolan"
}
{
"message": "Document floor",
"name": "Nicolas Williams"
}
- text: |
`.[]` returns each element of the array returned in the response, one at a
time, which are all fed into
`{message: .commit.message, name: .commit.committer.name}`.
Data in jq is represented as streams of JSON values - every jq
expression runs for each value in its input stream, and can
produce any number of values to its output stream.
Streams are serialised by just separating JSON values with
whitespace. This is a `cat`-friendly format - you can just join
two JSON streams together and get a valid JSON stream.
If you want to get the output as a single array, you can tell jq to
"collect" all of the answers by wrapping the filter in square
brackets:
- command: "jq '[.[] | {message: .commit.message, name: .commit.committer.name}]'"
result: |
[
{
"message": "Merge pull request #163 from stedolan/utf8-fixes\n\nUtf8 fixes. Closes #161",
"name": "Stephen Dolan"
},
{
"message": "Reject all overlong UTF8 sequences.",
"name": "Stephen Dolan"
},
{
"message": "Fix various UTF8 parsing bugs.\n\nIn particular, parse bad UTF8 by replacing the broken bits with U+FFFD\nand resychronise correctly after broken sequences.",
"name": "Stephen Dolan"
},
{
"message": "Fix example in manual for `floor`. See #155.",
"name": "Stephen Dolan"
},
{
"message": "Document floor",
"name": "Nicolas Williams"
}
]
- text: |
- - -
Next, let's try getting the URLs of the parent commits out of the
API results as well. In each commit, the GitHub API includes information
about "parent" commits. There can be one or many.
"parents": [
{
"sha": "54b9c9bdb225af5d886466d72f47eafc51acb4f7",
"url": "https://api.github.com/repos/stedolan/jq/commits/54b9c9bdb225af5d886466d72f47eafc51acb4f7",
"html_url": "https://github.com/stedolan/jq/commit/54b9c9bdb225af5d886466d72f47eafc51acb4f7"
},
{
"sha": "8b1b503609c161fea4b003a7179b3fbb2dd4345a",
"url": "https://api.github.com/repos/stedolan/jq/commits/8b1b503609c161fea4b003a7179b3fbb2dd4345a",
"html_url": "https://github.com/stedolan/jq/commit/8b1b503609c161fea4b003a7179b3fbb2dd4345a"
}
]
We want to pull out all of the "html_url" fields inside that array of parent
commits and make a simple list of strings to go along with the
"message" and "author" fields we already have.
- command: "jq '[.[] | {message: .commit.message, name: .commit.committer.name, parents: [.parents[].html_url]}]'"
result: |
[
{
"message": "Merge pull request #162 from stedolan/utf8-fixes\n\nUtf8 fixes. Closes #161",
"name": "Stephen Dolan",
"parents": [
"https://github.com/stedolan/jq/commit/54b9c9bdb225af5d886466d72f47eafc51acb4f7",
"https://github.com/stedolan/jq/commit/8b1b503609c161fea4b003a7179b3fbb2dd4345a"
]
},
{
"message": "Reject all overlong UTF8 sequences.",
"name": "Stephen Dolan",
"parents": [
"https://github.com/stedolan/jq/commit/ff48bd6ec538b01d1057be8e93b94eef6914e9ef"
]
},
{
"message": "Fix various UTF8 parsing bugs.\n\nIn particular, parse bad UTF8 by replacing the broken bits with U+FFFD\nand resychronise correctly after broken sequences.",
"name": "Stephen Dolan",
"parents": [
"https://github.com/stedolan/jq/commit/54b9c9bdb225af5d886466d72f47eafc51acb4f7"
]
},
{
"message": "Fix example in manual for `floor`. See #155.",
"name": "Stephen Dolan",
"parents": [
"https://github.com/stedolan/jq/commit/3dcdc582ea993afea3f5503a78a77675967ecdfa"
]
},
{
"message": "Document floor",
"name": "Nicolas Williams",
"parents": [
"https://github.com/stedolan/jq/commit/7c4171d414f647ab08bcd20c76a4d8ed68d9c602"
]
}
]
- text: |
Here we're making an object as before, but this time the `parents`
field is being set to `[.parents[].html_url]`, which collects
all of the parent commit URLs defined in the parents object.
- text: |
- - -
Here endeth the tutorial! There's lots more to play with. Go
read [the manual](../manual/) if you're interested, and [download
jq](../download/) if you haven't already.
|
