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
|
# cepis
Ruby client for the [public CEP API at cep.is](https://cep.is). Official
Correios data (DNE), refreshed every two weeks. No runtime dependencies:
`net/http`, `json` and `csv` come with Ruby.
```ruby
require "cepis"
address = Cepis.lookup("01001-000")
puts "#{address.logradouro} #{address.localidade} #{address.uf}"
# Praça da Sé São Paulo SP
```
## Installation
```sh
gem install cepis
```
Or, in a `Gemfile`:
```ruby
gem "cepis", git: "https://git.cep.is/ruby.git"
```
Requires Ruby 3.0 or newer.
## Usage
### A single lookup
`lookup` accepts the CEP masked or unmasked and returns a `Cepis::Address`:
```ruby
a = Cepis.lookup("01310-100")
a.logradouro # "Avenida Paulista"
a.localidade # "São Paulo"
a.uf # "SP"
a.ibge # "3550308"
a.cep # "01310100" (always unmasked)
a.formatted_cep # "01310-100"
```
Fields the database does not have for that CEP come back as empty strings,
never `nil`.
### Coordinates
About 57% of CEPs have a coordinate. When they do not, `geo` is `nil`:
```ruby
a = Cepis.lookup("01310100")
if a.geo
puts "#{a.geo.lat} #{a.geo.lon}" # -23.567202 -46.649659
puts a.geo.raio_m # 1084
puts a.geo.precisao # "logradouro"
end
```
**Check `precisao` before computing distance.** There are two kinds of point,
and the difference between them is tens of kilometres:
| `precisao` | typical radius | what the point is |
| --- | --- | --- |
| `logradouro` | 110–140 m | the stretch of street — good for maps and distance |
| `localidade` | 7–40 km | the municipality centroid: the CEP *is* the whole city |
`a.geo.precise?` is the shorthand for `precisao == "logradouro"`:
```ruby
cost = if a.geo&.precise?
shipping_from(a.geo.lat, a.geo.lon)
else
shipping_from_municipality(a.ibge)
end
```
### Many CEPs at once
Do not loop over `lookup`. Use `lookup_many`, which resolves up to 500 CEPs
per request:
```ruby
ceps = %w[01001000 99999999 20040020]
ceps.zip(Cepis.lookup_many(ceps)).each do |requested, address|
puts address.nil? ? "#{requested}: not found" : "#{requested}: #{address.localidade}"
end
```
The returned array has **the same length and the same order** as the input. A
CEP that does not exist, or is malformed, becomes `nil` at its position — it
does not vanish, and it does not raise.
Arrays longer than 500 are chunked automatically.
> **Batches carry no coordinate.** The endpoint behind them is CSV, and the
> CSV has no `geo` column. Every `Address` from `lookup_many` has `geo` set to
> `nil`, including for CEPs that do have one. Need `geo`? Use `lookup`, one at
> a time.
### API health
Useful for two things: checking the API answers, and knowing **which version
of the database** is live:
```ruby
h = Cepis.health
h.ok? # true
h.dne # "26071" identifier of the fortnightly database
h.ceps # 1596168
h.base_gerada_em # "2026-07-24T03:48:28Z"
```
An API reporting itself degraded does not raise — that arrives in `h.status`.
## Configuration
For anything beyond the defaults, build a `Cepis::Client` and reuse it. It
keeps no state between calls and is safe to share across threads:
```ruby
client = Cepis::Client.new(
base_url: "https://cep.is", # point at another instance
timeout: 10.0, # seconds per socket operation
max_attempts: 3, # counting the first; 1 disables retrying
backoff_base: 0.5, # base of the exponential wait
backoff_max: 8.0, # cap on each wait
total_timeout: nil # cap on the whole call, attempts included
)
address = client.lookup("01001000")
```
Retries cover 429, 5xx and network failures, with exponential backoff and
jitter; 400 and 404 are never retried.
The module-level methods (`Cepis.lookup`, etc.) use a shared default client.
Do not mutate it: it applies process-wide, including to third-party libraries
that also use this gem. Need a different configuration? Build your own.
### Pointing at a local instance
`base_url` is the only parameter that usually changes between environments.
The API repo brings a local instance up with `just up`:
```ruby
client = Cepis::Client.new(base_url: "http://localhost:8080")
```
## Errors
Everything derives from `Cepis::Error`, itself a `StandardError`. Below that,
the split is by **the decision you have to make**, not by the HTTP status that
caused it:
| error | when | does retrying help? |
| --- | --- | --- |
| `Cepis::InvalidCEP` | not 8 digits | no |
| `Cepis::CEPNotFound` | well-formed, not in the database | no |
| `Cepis::RateLimited` | 429 | yes, later |
| `Cepis::ServerError` | 5xx | yes, later |
| `Cepis::NetworkError` | DNS, connection, timeout, TLS | yes, later |
| `Cepis::InvalidResponse` | unintelligible response | probably not |
```ruby
begin
address = Cepis.lookup(cep_from_form)
rescue Cepis::CEPNotFound
# ask the user for another CEP
rescue Cepis::Error
# transient failure: reschedule
end
```
`RateLimited#retry_after` carries what the server asked for, in seconds, and
`ServerError#status` the HTTP status of the last attempt.
`InvalidResponse` almost always means something between you and the API is
answering instead of it — a captive Wi-Fi portal, a corporate proxy, an HTML
error page. Useful as a diagnosis: the problem is not in your code.
## Development
Everything runs through `make` and the Ruby on your `PATH`. There is nothing
to install: the gem and its suite use only the standard library, and the tests
bring up a real HTTP server on loopback.
```sh
make # list the targets
make test # run the suite (minitest)
make lint # ruby -w -c over the tree, plus a warning-clean load
make build # build the gem into pkg/
make check # lint, then test, then build
```
Ruby ships no linter or formatter, and this gem does not depend on one. `make
lint` is therefore a syntax and warning check; if `rubocop` happens to be
installed it is run as well, and `make format` applies it.
## Licence
ISC. See [LICENSE](LICENSE).
|