summaryrefslogtreecommitdiff
path: root/python-graphql-relay.spec
blob: ff879afc1a019c29bcce603c3441ab32ff827d01 (plain)
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
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
%global _empty_manifest_terminate_build 0
Name:		python-graphql-relay
Version:	3.2.0
Release:	1
Summary:	Relay library for graphql-core
License:	MIT
URL:		https://github.com/graphql-python/graphql-relay-py
Source0:	https://mirrors.nju.edu.cn/pypi/web/packages/d1/13/98fbf8d67552f102488ffc16c6f559ce71ea15f6294728d33928ab5ff14d/graphql-relay-3.2.0.tar.gz
BuildArch:	noarch

Requires:	python3-graphql-core
Requires:	python3-typing-extensions

%description
# Relay Library for GraphQL Python

GraphQL-relay-py is the [Relay](https://relay.dev/) library for
[GraphQL-core](https://github.com/graphql-python/graphql-core).

It allows the easy creation of Relay-compliant servers using GraphQL-core.

GraphQL-Relay-Py is a Python port of
[graphql-relay-js](https://github.com/graphql/graphql-relay-js),
while GraphQL-Core is a Python port of
[GraphQL.js](https://github.com/graphql/graphql-js),
the reference implementation of GraphQL for JavaScript.

Since version 3, GraphQL-Relay-Py and GraphQL-Core support Python 3.6 and above only.
For older versions of Python, you can use version 2 of these libraries.

[![PyPI version](https://badge.fury.io/py/graphql-relay.svg)](https://badge.fury.io/py/graphql-relay)
![Test Status](https://github.com/graphql-python/graphql-relay-py/actions/workflows/test.yml/badge.svg)
![Lint Status](https://github.com/graphql-python/graphql-relay-py/actions/workflows/lint.yml/badge.svg)
[![Dependency Updates](https://pyup.io/repos/github/graphql-python/graphql-relay-py/shield.svg)](https://pyup.io/repos/github/graphql-python/graphql-relay-py/)
[![Python 3 Status](https://pyup.io/repos/github/graphql-python/graphql-relay-py/python-3-shield.svg)](https://pyup.io/repos/github/graphql-python/graphql-relay-py/)
[![Code Style](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black)

## Getting Started

A basic understanding of GraphQL and of the GraphQL Python implementation is needed
to provide context for this library.

An overview of GraphQL in general is available in the
[README](https://github.com/graphql-python/graphql-core/blob/master/README.md) for the
[Specification for GraphQL](https://github.com/graphql-python/graphql-core).

This library is designed to work with the
the [GraphQL-Core](https://github.com/graphql-python/graphql-core)
Python reference implementation of a GraphQL server.

An overview of the functionality that a Relay-compliant GraphQL server should provide
is in the [GraphQL Relay Specification](https://facebook.github.io/relay/docs/graphql-relay-specification.html)
on the [Relay website](https://facebook.github.io/relay/).
That overview describes a simple set of examples that exist
as [tests](tests) in this repository.
A good way to get started with this repository is to walk through that documentation
and the corresponding tests in this library together.

## Using Relay Library for GraphQL Python (graphql-core)

Install Relay Library for GraphQL Python

```sh
pip install graphql-core
pip install graphql-relay
```

When building a schema for [GraphQL](https://github.com/graphql-python/graphql-core),
the provided library functions can be used to simplify the creation of Relay patterns.

All the functions that are explained in the following sections must be
imported from the top level of the `graphql_relay` package, like this:
```python
from graphql_relay import connection_definitions
```

### Connections

Helper functions are provided for both building the GraphQL types
for connections and for implementing the `resolve` method for fields
returning those types.

 - `connection_args` returns the arguments that fields should provide when
they return a connection type that supports bidirectional pagination.
 - `forward_connection_args` returns the arguments that fields should provide when
they return a connection type that only supports forward pagination.
 - `backward_connection_args` returns the arguments that fields should provide when
they return a connection type that only supports backward pagination.
 - `connection_definitions` returns a `connection_type` and its associated
`edgeType`, given a name and a node type.
 - `connection_from_array` is a helper method that takes an array and the
arguments from `connection_args`, does pagination and filtering, and returns
an object in the shape expected by a `connection_type`'s `resolve` function.
 - `cursor_for_object_in_connection` is a helper method that takes an array and a
member object, and returns a cursor for use in the mutation payload.
 - `offset_to_cursor` takes the index of a member object in an array
 and returns an opaque cursor for use in the mutation payload.
 - `cursor_to_offset` takes an opaque cursor (created with `offset_to_cursor`)
and returns the corresponding array index.

An example usage of these methods from the [test schema](tests/star_wars_schema.py):

```python
ship_edge, ship_connection = connection_definitions(ship_type, "Ship")

faction_type = GraphQLObjectType(
    name="Faction",
    description="A faction in the Star Wars saga",
    fields=lambda: {
        "id": global_id_field("Faction"),
        "name": GraphQLField(GraphQLString, description="The name of the faction."),
        "ships": GraphQLField(
            ship_connection,
            description="The ships used by the faction.",
            args=connection_args,
            resolve=lambda faction, _info, **args: connection_from_array(
                [get_ship(ship) for ship in faction.ships], args
            ),
        ),
    },
    interfaces=[node_interface],
)
```

This shows adding a `ships` field to the `Faction` object that is a connection.
It uses `connection_definitions(ship_type, "Ship")` to create the connection
type, adds `connection_args` as arguments on this function, and then implements
the resolver function by passing the array of ships and the arguments to
`connection_from_array`.

### Object Identification

Helper functions are provided for both building the GraphQL types
for nodes and for implementing global IDs around local IDs.

 - `node_definitions` returns the `Node` interface that objects can implement,
    and returns the `node` root field to include on the query type.
    To implement this, it takes a function to resolve an ID to an object,
    and to determine the type of a given object.
 - `to_global_id` takes a type name and an ID specific to that type name,
    and returns a "global ID" that is unique among all types.
 - `from_global_id` takes the "global ID" created by `to_global_id`, and
    returns the type name and ID used to create it.
 - `global_id_field` creates the configuration for an `id` field on a node.
 - `plural_identifying_root_field` creates a field that accepts a list of
    non-ID identifiers (like a username) and maps then to their corresponding
    objects.

An example usage of these methods from the [test schema](tests/star_wars_schema.py):

```python
def get_node(global_id, _info):
    type_, id_ = from_global_id(global_id)
    if type_ == "Faction":
        return get_faction(id_)
    if type_ == "Ship":
        return get_ship(id_)
    return None  # pragma: no cover

def get_node_type(obj, _info, _type):
    if isinstance(obj, Faction):
        return faction_type.name
    return ship_type.name

node_interface, node_field = node_definitions(get_node, get_node_type)[:2]

faction_type = GraphQLObjectType(
    name="Faction",
    description="A faction in the Star Wars saga",
    fields=lambda: {
        "id": global_id_field("Faction"),
        "name": GraphQLField(GraphQLString, description="The name of the faction."),
        "ships": GraphQLField(
            ship_connection,
            description="The ships used by the faction.",
            args=connection_args,
            resolve=lambda faction, _info, **args: connection_from_array(
                [get_ship(ship) for ship in faction.ships], args
            ),
        ),
    },
    interfaces=[node_interface],
)

query_type = GraphQLObjectType(
    name="Query",
    fields=lambda: {
        "rebels": GraphQLField(faction_type, resolve=lambda _obj, _info: get_rebels()),
        "empire": GraphQLField(faction_type, resolve=lambda _obj, _info: get_empire()),
        "node": node_field,
    },
)
```

This uses `node_definitions` to construct the `Node` interface and the `node`
field; it uses `from_global_id` to resolve the IDs passed in the implementation
of the function mapping ID to object. It then uses the `global_id_field` method to
create the `id` field on `Faction`, which also ensures implements the
`node_interface`. Finally, it adds the `node` field to the query type, using the
`node_field` returned by `node_definitions`.

### Mutations

A helper function is provided for building mutations with
single inputs and client mutation IDs.

 - `mutation_with_client_mutation_id` takes a name, input fields, output fields,
and a mutation method to map from the input fields to the output fields,
performing the mutation along the way. It then creates and returns a field
configuration that can be used as a top-level field on the mutation type.

An example usage of these methods from the [test schema](tests/star_wars_schema.py):

```python
class IntroduceShipMutation:

    def __init__(self, shipId, factionId, clientMutationId=None):
        self.shipId = shipId
        self.factionId = factionId
        self.clientMutationId = clientMutationId

def mutate_and_get_payload(_info, shipName, factionId, **_input):
    new_ship = create_ship(shipName, factionId)
    return IntroduceShipMutation(shipId=new_ship.id, factionId=factionId)

ship_mutation = mutation_with_client_mutation_id(
    "IntroduceShip",
    input_fields={
        "shipName": GraphQLInputField(GraphQLNonNull(GraphQLString)),
        "factionId": GraphQLInputField(GraphQLNonNull(GraphQLID)),
    },
    output_fields={
        "ship": GraphQLField(
            ship_type, resolve=lambda payload, _info: get_ship(payload.shipId)
        ),
        "faction": GraphQLField(
            faction_type, resolve=lambda payload, _info: get_faction(payload.factionId)
        ),
    },
    mutate_and_get_payload=mutate_and_get_payload,
)

mutation_type = GraphQLObjectType(
    "Mutation", fields=lambda: {"introduceShip": ship_mutation}
)
```

This code creates a mutation named `IntroduceShip`, which takes a faction
ID and a ship name as input. It outputs the `Faction` and the `Ship` in
question. `mutate_and_get_payload` then gets each input field as keyword
parameter, performs the mutation by constructing the new ship, then returns
an object that will be resolved by the output fields.

Our mutation type then creates the `introduceShip` field using the return
value of `mutation_with_client_mutation_id`.

## Contributing

After cloning this repository from GitHub,
we recommend using [Poetry](https://poetry.eustace.io/)
to create a test environment. With poetry installed,
you do this with the following command:

```sh
poetry install
```

You can then run the complete test suite like this:

```sh
poetry run pytest
```

In order to run only a part of the tests with increased verbosity,
you can add pytest options, like this:

```sh
poetry run pytest tests/node -vv
```

In order to check the code style with flake8, use this:

```sh
poetry run flake8
```

Use the `tox` command to run the test suite with different
Python versions and perform all additional source code checks.
You can also restrict tox to an individual environment, like this:

```sh
poetry run tox -e py39
```




%package -n python3-graphql-relay
Summary:	Relay library for graphql-core
Provides:	python-graphql-relay
BuildRequires:	python3-devel
BuildRequires:	python3-setuptools
BuildRequires:	python3-pip
%description -n python3-graphql-relay
# Relay Library for GraphQL Python

GraphQL-relay-py is the [Relay](https://relay.dev/) library for
[GraphQL-core](https://github.com/graphql-python/graphql-core).

It allows the easy creation of Relay-compliant servers using GraphQL-core.

GraphQL-Relay-Py is a Python port of
[graphql-relay-js](https://github.com/graphql/graphql-relay-js),
while GraphQL-Core is a Python port of
[GraphQL.js](https://github.com/graphql/graphql-js),
the reference implementation of GraphQL for JavaScript.

Since version 3, GraphQL-Relay-Py and GraphQL-Core support Python 3.6 and above only.
For older versions of Python, you can use version 2 of these libraries.

[![PyPI version](https://badge.fury.io/py/graphql-relay.svg)](https://badge.fury.io/py/graphql-relay)
![Test Status](https://github.com/graphql-python/graphql-relay-py/actions/workflows/test.yml/badge.svg)
![Lint Status](https://github.com/graphql-python/graphql-relay-py/actions/workflows/lint.yml/badge.svg)
[![Dependency Updates](https://pyup.io/repos/github/graphql-python/graphql-relay-py/shield.svg)](https://pyup.io/repos/github/graphql-python/graphql-relay-py/)
[![Python 3 Status](https://pyup.io/repos/github/graphql-python/graphql-relay-py/python-3-shield.svg)](https://pyup.io/repos/github/graphql-python/graphql-relay-py/)
[![Code Style](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black)

## Getting Started

A basic understanding of GraphQL and of the GraphQL Python implementation is needed
to provide context for this library.

An overview of GraphQL in general is available in the
[README](https://github.com/graphql-python/graphql-core/blob/master/README.md) for the
[Specification for GraphQL](https://github.com/graphql-python/graphql-core).

This library is designed to work with the
the [GraphQL-Core](https://github.com/graphql-python/graphql-core)
Python reference implementation of a GraphQL server.

An overview of the functionality that a Relay-compliant GraphQL server should provide
is in the [GraphQL Relay Specification](https://facebook.github.io/relay/docs/graphql-relay-specification.html)
on the [Relay website](https://facebook.github.io/relay/).
That overview describes a simple set of examples that exist
as [tests](tests) in this repository.
A good way to get started with this repository is to walk through that documentation
and the corresponding tests in this library together.

## Using Relay Library for GraphQL Python (graphql-core)

Install Relay Library for GraphQL Python

```sh
pip install graphql-core
pip install graphql-relay
```

When building a schema for [GraphQL](https://github.com/graphql-python/graphql-core),
the provided library functions can be used to simplify the creation of Relay patterns.

All the functions that are explained in the following sections must be
imported from the top level of the `graphql_relay` package, like this:
```python
from graphql_relay import connection_definitions
```

### Connections

Helper functions are provided for both building the GraphQL types
for connections and for implementing the `resolve` method for fields
returning those types.

 - `connection_args` returns the arguments that fields should provide when
they return a connection type that supports bidirectional pagination.
 - `forward_connection_args` returns the arguments that fields should provide when
they return a connection type that only supports forward pagination.
 - `backward_connection_args` returns the arguments that fields should provide when
they return a connection type that only supports backward pagination.
 - `connection_definitions` returns a `connection_type` and its associated
`edgeType`, given a name and a node type.
 - `connection_from_array` is a helper method that takes an array and the
arguments from `connection_args`, does pagination and filtering, and returns
an object in the shape expected by a `connection_type`'s `resolve` function.
 - `cursor_for_object_in_connection` is a helper method that takes an array and a
member object, and returns a cursor for use in the mutation payload.
 - `offset_to_cursor` takes the index of a member object in an array
 and returns an opaque cursor for use in the mutation payload.
 - `cursor_to_offset` takes an opaque cursor (created with `offset_to_cursor`)
and returns the corresponding array index.

An example usage of these methods from the [test schema](tests/star_wars_schema.py):

```python
ship_edge, ship_connection = connection_definitions(ship_type, "Ship")

faction_type = GraphQLObjectType(
    name="Faction",
    description="A faction in the Star Wars saga",
    fields=lambda: {
        "id": global_id_field("Faction"),
        "name": GraphQLField(GraphQLString, description="The name of the faction."),
        "ships": GraphQLField(
            ship_connection,
            description="The ships used by the faction.",
            args=connection_args,
            resolve=lambda faction, _info, **args: connection_from_array(
                [get_ship(ship) for ship in faction.ships], args
            ),
        ),
    },
    interfaces=[node_interface],
)
```

This shows adding a `ships` field to the `Faction` object that is a connection.
It uses `connection_definitions(ship_type, "Ship")` to create the connection
type, adds `connection_args` as arguments on this function, and then implements
the resolver function by passing the array of ships and the arguments to
`connection_from_array`.

### Object Identification

Helper functions are provided for both building the GraphQL types
for nodes and for implementing global IDs around local IDs.

 - `node_definitions` returns the `Node` interface that objects can implement,
    and returns the `node` root field to include on the query type.
    To implement this, it takes a function to resolve an ID to an object,
    and to determine the type of a given object.
 - `to_global_id` takes a type name and an ID specific to that type name,
    and returns a "global ID" that is unique among all types.
 - `from_global_id` takes the "global ID" created by `to_global_id`, and
    returns the type name and ID used to create it.
 - `global_id_field` creates the configuration for an `id` field on a node.
 - `plural_identifying_root_field` creates a field that accepts a list of
    non-ID identifiers (like a username) and maps then to their corresponding
    objects.

An example usage of these methods from the [test schema](tests/star_wars_schema.py):

```python
def get_node(global_id, _info):
    type_, id_ = from_global_id(global_id)
    if type_ == "Faction":
        return get_faction(id_)
    if type_ == "Ship":
        return get_ship(id_)
    return None  # pragma: no cover

def get_node_type(obj, _info, _type):
    if isinstance(obj, Faction):
        return faction_type.name
    return ship_type.name

node_interface, node_field = node_definitions(get_node, get_node_type)[:2]

faction_type = GraphQLObjectType(
    name="Faction",
    description="A faction in the Star Wars saga",
    fields=lambda: {
        "id": global_id_field("Faction"),
        "name": GraphQLField(GraphQLString, description="The name of the faction."),
        "ships": GraphQLField(
            ship_connection,
            description="The ships used by the faction.",
            args=connection_args,
            resolve=lambda faction, _info, **args: connection_from_array(
                [get_ship(ship) for ship in faction.ships], args
            ),
        ),
    },
    interfaces=[node_interface],
)

query_type = GraphQLObjectType(
    name="Query",
    fields=lambda: {
        "rebels": GraphQLField(faction_type, resolve=lambda _obj, _info: get_rebels()),
        "empire": GraphQLField(faction_type, resolve=lambda _obj, _info: get_empire()),
        "node": node_field,
    },
)
```

This uses `node_definitions` to construct the `Node` interface and the `node`
field; it uses `from_global_id` to resolve the IDs passed in the implementation
of the function mapping ID to object. It then uses the `global_id_field` method to
create the `id` field on `Faction`, which also ensures implements the
`node_interface`. Finally, it adds the `node` field to the query type, using the
`node_field` returned by `node_definitions`.

### Mutations

A helper function is provided for building mutations with
single inputs and client mutation IDs.

 - `mutation_with_client_mutation_id` takes a name, input fields, output fields,
and a mutation method to map from the input fields to the output fields,
performing the mutation along the way. It then creates and returns a field
configuration that can be used as a top-level field on the mutation type.

An example usage of these methods from the [test schema](tests/star_wars_schema.py):

```python
class IntroduceShipMutation:

    def __init__(self, shipId, factionId, clientMutationId=None):
        self.shipId = shipId
        self.factionId = factionId
        self.clientMutationId = clientMutationId

def mutate_and_get_payload(_info, shipName, factionId, **_input):
    new_ship = create_ship(shipName, factionId)
    return IntroduceShipMutation(shipId=new_ship.id, factionId=factionId)

ship_mutation = mutation_with_client_mutation_id(
    "IntroduceShip",
    input_fields={
        "shipName": GraphQLInputField(GraphQLNonNull(GraphQLString)),
        "factionId": GraphQLInputField(GraphQLNonNull(GraphQLID)),
    },
    output_fields={
        "ship": GraphQLField(
            ship_type, resolve=lambda payload, _info: get_ship(payload.shipId)
        ),
        "faction": GraphQLField(
            faction_type, resolve=lambda payload, _info: get_faction(payload.factionId)
        ),
    },
    mutate_and_get_payload=mutate_and_get_payload,
)

mutation_type = GraphQLObjectType(
    "Mutation", fields=lambda: {"introduceShip": ship_mutation}
)
```

This code creates a mutation named `IntroduceShip`, which takes a faction
ID and a ship name as input. It outputs the `Faction` and the `Ship` in
question. `mutate_and_get_payload` then gets each input field as keyword
parameter, performs the mutation by constructing the new ship, then returns
an object that will be resolved by the output fields.

Our mutation type then creates the `introduceShip` field using the return
value of `mutation_with_client_mutation_id`.

## Contributing

After cloning this repository from GitHub,
we recommend using [Poetry](https://poetry.eustace.io/)
to create a test environment. With poetry installed,
you do this with the following command:

```sh
poetry install
```

You can then run the complete test suite like this:

```sh
poetry run pytest
```

In order to run only a part of the tests with increased verbosity,
you can add pytest options, like this:

```sh
poetry run pytest tests/node -vv
```

In order to check the code style with flake8, use this:

```sh
poetry run flake8
```

Use the `tox` command to run the test suite with different
Python versions and perform all additional source code checks.
You can also restrict tox to an individual environment, like this:

```sh
poetry run tox -e py39
```




%package help
Summary:	Development documents and examples for graphql-relay
Provides:	python3-graphql-relay-doc
%description help
# Relay Library for GraphQL Python

GraphQL-relay-py is the [Relay](https://relay.dev/) library for
[GraphQL-core](https://github.com/graphql-python/graphql-core).

It allows the easy creation of Relay-compliant servers using GraphQL-core.

GraphQL-Relay-Py is a Python port of
[graphql-relay-js](https://github.com/graphql/graphql-relay-js),
while GraphQL-Core is a Python port of
[GraphQL.js](https://github.com/graphql/graphql-js),
the reference implementation of GraphQL for JavaScript.

Since version 3, GraphQL-Relay-Py and GraphQL-Core support Python 3.6 and above only.
For older versions of Python, you can use version 2 of these libraries.

[![PyPI version](https://badge.fury.io/py/graphql-relay.svg)](https://badge.fury.io/py/graphql-relay)
![Test Status](https://github.com/graphql-python/graphql-relay-py/actions/workflows/test.yml/badge.svg)
![Lint Status](https://github.com/graphql-python/graphql-relay-py/actions/workflows/lint.yml/badge.svg)
[![Dependency Updates](https://pyup.io/repos/github/graphql-python/graphql-relay-py/shield.svg)](https://pyup.io/repos/github/graphql-python/graphql-relay-py/)
[![Python 3 Status](https://pyup.io/repos/github/graphql-python/graphql-relay-py/python-3-shield.svg)](https://pyup.io/repos/github/graphql-python/graphql-relay-py/)
[![Code Style](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black)

## Getting Started

A basic understanding of GraphQL and of the GraphQL Python implementation is needed
to provide context for this library.

An overview of GraphQL in general is available in the
[README](https://github.com/graphql-python/graphql-core/blob/master/README.md) for the
[Specification for GraphQL](https://github.com/graphql-python/graphql-core).

This library is designed to work with the
the [GraphQL-Core](https://github.com/graphql-python/graphql-core)
Python reference implementation of a GraphQL server.

An overview of the functionality that a Relay-compliant GraphQL server should provide
is in the [GraphQL Relay Specification](https://facebook.github.io/relay/docs/graphql-relay-specification.html)
on the [Relay website](https://facebook.github.io/relay/).
That overview describes a simple set of examples that exist
as [tests](tests) in this repository.
A good way to get started with this repository is to walk through that documentation
and the corresponding tests in this library together.

## Using Relay Library for GraphQL Python (graphql-core)

Install Relay Library for GraphQL Python

```sh
pip install graphql-core
pip install graphql-relay
```

When building a schema for [GraphQL](https://github.com/graphql-python/graphql-core),
the provided library functions can be used to simplify the creation of Relay patterns.

All the functions that are explained in the following sections must be
imported from the top level of the `graphql_relay` package, like this:
```python
from graphql_relay import connection_definitions
```

### Connections

Helper functions are provided for both building the GraphQL types
for connections and for implementing the `resolve` method for fields
returning those types.

 - `connection_args` returns the arguments that fields should provide when
they return a connection type that supports bidirectional pagination.
 - `forward_connection_args` returns the arguments that fields should provide when
they return a connection type that only supports forward pagination.
 - `backward_connection_args` returns the arguments that fields should provide when
they return a connection type that only supports backward pagination.
 - `connection_definitions` returns a `connection_type` and its associated
`edgeType`, given a name and a node type.
 - `connection_from_array` is a helper method that takes an array and the
arguments from `connection_args`, does pagination and filtering, and returns
an object in the shape expected by a `connection_type`'s `resolve` function.
 - `cursor_for_object_in_connection` is a helper method that takes an array and a
member object, and returns a cursor for use in the mutation payload.
 - `offset_to_cursor` takes the index of a member object in an array
 and returns an opaque cursor for use in the mutation payload.
 - `cursor_to_offset` takes an opaque cursor (created with `offset_to_cursor`)
and returns the corresponding array index.

An example usage of these methods from the [test schema](tests/star_wars_schema.py):

```python
ship_edge, ship_connection = connection_definitions(ship_type, "Ship")

faction_type = GraphQLObjectType(
    name="Faction",
    description="A faction in the Star Wars saga",
    fields=lambda: {
        "id": global_id_field("Faction"),
        "name": GraphQLField(GraphQLString, description="The name of the faction."),
        "ships": GraphQLField(
            ship_connection,
            description="The ships used by the faction.",
            args=connection_args,
            resolve=lambda faction, _info, **args: connection_from_array(
                [get_ship(ship) for ship in faction.ships], args
            ),
        ),
    },
    interfaces=[node_interface],
)
```

This shows adding a `ships` field to the `Faction` object that is a connection.
It uses `connection_definitions(ship_type, "Ship")` to create the connection
type, adds `connection_args` as arguments on this function, and then implements
the resolver function by passing the array of ships and the arguments to
`connection_from_array`.

### Object Identification

Helper functions are provided for both building the GraphQL types
for nodes and for implementing global IDs around local IDs.

 - `node_definitions` returns the `Node` interface that objects can implement,
    and returns the `node` root field to include on the query type.
    To implement this, it takes a function to resolve an ID to an object,
    and to determine the type of a given object.
 - `to_global_id` takes a type name and an ID specific to that type name,
    and returns a "global ID" that is unique among all types.
 - `from_global_id` takes the "global ID" created by `to_global_id`, and
    returns the type name and ID used to create it.
 - `global_id_field` creates the configuration for an `id` field on a node.
 - `plural_identifying_root_field` creates a field that accepts a list of
    non-ID identifiers (like a username) and maps then to their corresponding
    objects.

An example usage of these methods from the [test schema](tests/star_wars_schema.py):

```python
def get_node(global_id, _info):
    type_, id_ = from_global_id(global_id)
    if type_ == "Faction":
        return get_faction(id_)
    if type_ == "Ship":
        return get_ship(id_)
    return None  # pragma: no cover

def get_node_type(obj, _info, _type):
    if isinstance(obj, Faction):
        return faction_type.name
    return ship_type.name

node_interface, node_field = node_definitions(get_node, get_node_type)[:2]

faction_type = GraphQLObjectType(
    name="Faction",
    description="A faction in the Star Wars saga",
    fields=lambda: {
        "id": global_id_field("Faction"),
        "name": GraphQLField(GraphQLString, description="The name of the faction."),
        "ships": GraphQLField(
            ship_connection,
            description="The ships used by the faction.",
            args=connection_args,
            resolve=lambda faction, _info, **args: connection_from_array(
                [get_ship(ship) for ship in faction.ships], args
            ),
        ),
    },
    interfaces=[node_interface],
)

query_type = GraphQLObjectType(
    name="Query",
    fields=lambda: {
        "rebels": GraphQLField(faction_type, resolve=lambda _obj, _info: get_rebels()),
        "empire": GraphQLField(faction_type, resolve=lambda _obj, _info: get_empire()),
        "node": node_field,
    },
)
```

This uses `node_definitions` to construct the `Node` interface and the `node`
field; it uses `from_global_id` to resolve the IDs passed in the implementation
of the function mapping ID to object. It then uses the `global_id_field` method to
create the `id` field on `Faction`, which also ensures implements the
`node_interface`. Finally, it adds the `node` field to the query type, using the
`node_field` returned by `node_definitions`.

### Mutations

A helper function is provided for building mutations with
single inputs and client mutation IDs.

 - `mutation_with_client_mutation_id` takes a name, input fields, output fields,
and a mutation method to map from the input fields to the output fields,
performing the mutation along the way. It then creates and returns a field
configuration that can be used as a top-level field on the mutation type.

An example usage of these methods from the [test schema](tests/star_wars_schema.py):

```python
class IntroduceShipMutation:

    def __init__(self, shipId, factionId, clientMutationId=None):
        self.shipId = shipId
        self.factionId = factionId
        self.clientMutationId = clientMutationId

def mutate_and_get_payload(_info, shipName, factionId, **_input):
    new_ship = create_ship(shipName, factionId)
    return IntroduceShipMutation(shipId=new_ship.id, factionId=factionId)

ship_mutation = mutation_with_client_mutation_id(
    "IntroduceShip",
    input_fields={
        "shipName": GraphQLInputField(GraphQLNonNull(GraphQLString)),
        "factionId": GraphQLInputField(GraphQLNonNull(GraphQLID)),
    },
    output_fields={
        "ship": GraphQLField(
            ship_type, resolve=lambda payload, _info: get_ship(payload.shipId)
        ),
        "faction": GraphQLField(
            faction_type, resolve=lambda payload, _info: get_faction(payload.factionId)
        ),
    },
    mutate_and_get_payload=mutate_and_get_payload,
)

mutation_type = GraphQLObjectType(
    "Mutation", fields=lambda: {"introduceShip": ship_mutation}
)
```

This code creates a mutation named `IntroduceShip`, which takes a faction
ID and a ship name as input. It outputs the `Faction` and the `Ship` in
question. `mutate_and_get_payload` then gets each input field as keyword
parameter, performs the mutation by constructing the new ship, then returns
an object that will be resolved by the output fields.

Our mutation type then creates the `introduceShip` field using the return
value of `mutation_with_client_mutation_id`.

## Contributing

After cloning this repository from GitHub,
we recommend using [Poetry](https://poetry.eustace.io/)
to create a test environment. With poetry installed,
you do this with the following command:

```sh
poetry install
```

You can then run the complete test suite like this:

```sh
poetry run pytest
```

In order to run only a part of the tests with increased verbosity,
you can add pytest options, like this:

```sh
poetry run pytest tests/node -vv
```

In order to check the code style with flake8, use this:

```sh
poetry run flake8
```

Use the `tox` command to run the test suite with different
Python versions and perform all additional source code checks.
You can also restrict tox to an individual environment, like this:

```sh
poetry run tox -e py39
```




%prep
%autosetup -n graphql-relay-3.2.0

%build
%py3_build

%install
%py3_install
install -d -m755 %{buildroot}/%{_pkgdocdir}
if [ -d doc ]; then cp -arf doc %{buildroot}/%{_pkgdocdir}; fi
if [ -d docs ]; then cp -arf docs %{buildroot}/%{_pkgdocdir}; fi
if [ -d example ]; then cp -arf example %{buildroot}/%{_pkgdocdir}; fi
if [ -d examples ]; then cp -arf examples %{buildroot}/%{_pkgdocdir}; fi
pushd %{buildroot}
if [ -d usr/lib ]; then
	find usr/lib -type f -printf "/%h/%f\n" >> filelist.lst
fi
if [ -d usr/lib64 ]; then
	find usr/lib64 -type f -printf "/%h/%f\n" >> filelist.lst
fi
if [ -d usr/bin ]; then
	find usr/bin -type f -printf "/%h/%f\n" >> filelist.lst
fi
if [ -d usr/sbin ]; then
	find usr/sbin -type f -printf "/%h/%f\n" >> filelist.lst
fi
touch doclist.lst
if [ -d usr/share/man ]; then
	find usr/share/man -type f -printf "/%h/%f.gz\n" >> doclist.lst
fi
popd
mv %{buildroot}/filelist.lst .
mv %{buildroot}/doclist.lst .

%files -n python3-graphql-relay -f filelist.lst
%dir %{python3_sitelib}/*

%files help -f doclist.lst
%{_docdir}/*

%changelog
* Thu Mar 09 2023 Python_Bot <Python_Bot@openeuler.org> - 3.2.0-1
- Package Spec generated