CherryPy_subhandler / cherrypy / test / test_conn.py

  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
"""Tests for TCP connection handling, including proper and timely close."""

from cherrypy.test import test
test.prefer_parent_path()

import httplib
import urllib
import socket
import sys
import time
timeout = 1


import cherrypy
from cherrypy.test import webtest
from cherrypy import _cperror


pov = 'pPeErRsSiIsStTeEnNcCeE oOfF vViIsSiIoOnN'

def setup_server():
    
    def raise500():
        raise cherrypy.HTTPError(500)
    
    class Root:
        
        def index(self):
            return pov
        index.exposed = True
        page1 = index
        page2 = index
        page3 = index
        
        def hello(self):
            return "Hello, world!"
        hello.exposed = True
        
        def timeout(self, t):
            return str(cherrypy.server.httpserver.timeout)
        timeout.exposed = True
        
        def stream(self, set_cl=False):
            if set_cl:
                cherrypy.response.headers['Content-Length'] = 10
            
            def content():
                for x in xrange(10):
                    yield str(x)
            
            return content()
        stream.exposed = True
        stream._cp_config = {'response.stream': True}
        
        def error(self, code=500):
            raise cherrypy.HTTPError(code)
        error.exposed = True
        
        def upload(self):
            if not cherrypy.request.method == 'POST':
                raise AssertionError("'POST' != request.method %r" %
                                     cherrypy.request.method)
            return ("thanks for '%s' (%s)" %
                    (cherrypy.request.body.read(),
                     cherrypy.request.headers['Content-Type']))
        upload.exposed = True
        
        def custom(self, response_code):
            cherrypy.response.status = response_code
            return "Code = %s" % response_code
        custom.exposed = True
        
        def err_before_read(self):
            return "ok"
        err_before_read.exposed = True
        err_before_read._cp_config = {'hooks.on_start_resource': raise500}

        def one_megabyte_of_a(self):
            return ["a" * 1024] * 1024
        one_megabyte_of_a.exposed = True
    
    cherrypy.tree.mount(Root())
    cherrypy.config.update({
        'server.max_request_body_size': 1001,
        'environment': 'test_suite',
        })
    cherrypy.server.httpserver.timeout = timeout


from cherrypy.test import helper

class ConnectionTests(helper.CPWebCase):
    
    def test_HTTP11(self):
        if cherrypy.server.protocol_version != "HTTP/1.1":
            print "skipped ",
            return
        
        self.PROTOCOL = "HTTP/1.1"
        
        self.persistent = True
        
        # Make the first request and assert there's no "Connection: close".
        self.getPage("/")
        self.assertStatus('200 OK')
        self.assertBody(pov)
        self.assertNoHeader("Connection")
        
        # Make another request on the same connection.
        self.getPage("/page1")
        self.assertStatus('200 OK')
        self.assertBody(pov)
        self.assertNoHeader("Connection")
        
        # Test client-side close.
        self.getPage("/page2", headers=[("Connection", "close")])
        self.assertStatus('200 OK')
        self.assertBody(pov)
        self.assertHeader("Connection", "close")
        
        # Make another request on the same connection, which should error.
        self.assertRaises(httplib.NotConnected, self.getPage, "/")
    
    def test_Streaming_no_len(self):
        self._streaming(set_cl=False)
    
    def test_Streaming_with_len(self):
        self._streaming(set_cl=True)
    
    def _streaming(self, set_cl):
        if cherrypy.server.protocol_version == "HTTP/1.1":
            self.PROTOCOL = "HTTP/1.1"
            
            self.persistent = True
            
            # Make the first request and assert there's no "Connection: close".
            self.getPage("/")
            self.assertStatus('200 OK')
            self.assertBody(pov)
            self.assertNoHeader("Connection")
            
            # Make another, streamed request on the same connection.
            if set_cl:
                # When a Content-Length is provided, the content should stream
                # without closing the connection.
                self.getPage("/stream?set_cl=Yes")
                self.assertHeader("Content-Length")
                self.assertNoHeader("Connection", "close")
                self.assertNoHeader("Transfer-Encoding")
                
                self.assertStatus('200 OK')
                self.assertBody('0123456789')
            else:
                # When no Content-Length response header is provided,
                # streamed output will either close the connection, or use
                # chunked encoding, to determine transfer-length.
                self.getPage("/stream")
                self.assertNoHeader("Content-Length")
                self.assertStatus('200 OK')
                self.assertBody('0123456789')
                
                chunked_response = False
                for k, v in self.headers:
                    if k.lower() == "transfer-encoding":
                        if str(v) == "chunked":
                            chunked_response = True
                
                if chunked_response:
                    self.assertNoHeader("Connection", "close")
                else:
                    self.assertHeader("Connection", "close")
                    
                    # Make another request on the same connection, which should error.
                    self.assertRaises(httplib.NotConnected, self.getPage, "/")
                
                # Try HEAD. See http://www.cherrypy.org/ticket/864.
                self.getPage("/stream", method='HEAD')
                self.assertStatus('200 OK')
                self.assertBody('')
                self.assertNoHeader("Transfer-Encoding")
        else:
            self.PROTOCOL = "HTTP/1.0"
            
            self.persistent = True
            
            # Make the first request and assert Keep-Alive.
            self.getPage("/", headers=[("Connection", "Keep-Alive")])
            self.assertStatus('200 OK')
            self.assertBody(pov)
            self.assertHeader("Connection", "Keep-Alive")
            
            # Make another, streamed request on the same connection.
            if set_cl:
                # When a Content-Length is provided, the content should
                # stream without closing the connection.
                self.getPage("/stream?set_cl=Yes",
                             headers=[("Connection", "Keep-Alive")])
                self.assertHeader("Content-Length")
                self.assertHeader("Connection", "Keep-Alive")
                self.assertNoHeader("Transfer-Encoding")
                self.assertStatus('200 OK')
                self.assertBody('0123456789')
            else:
                # When a Content-Length is not provided,
                # the server should close the connection.
                self.getPage("/stream", headers=[("Connection", "Keep-Alive")])
                self.assertStatus('200 OK')
                self.assertBody('0123456789')
                
                self.assertNoHeader("Content-Length")
                self.assertNoHeader("Connection", "Keep-Alive")
                self.assertNoHeader("Transfer-Encoding")
                
                # Make another request on the same connection, which should error.
                self.assertRaises(httplib.NotConnected, self.getPage, "/")
    
    def test_HTTP11_Timeout(self):
        # If we timeout without sending any data,
        # the server will close the conn with a 408.
        if cherrypy.server.protocol_version != "HTTP/1.1":
            print "skipped",
            return
        
        self.PROTOCOL = "HTTP/1.1"
        
        # Connect but send nothing.
        self.persistent = True
        conn = self.HTTP_CONN
        conn.auto_open = False
        conn.connect()
        
        # Wait for our socket timeout
        time.sleep(timeout * 2)
        
        # The request should have returned 408 already.
        response = conn.response_class(conn.sock, method="GET")
        response.begin()
        self.assertEqual(response.status, 408)
        conn.close()
        
        # Connect but send half the headers only.
        self.persistent = True
        conn = self.HTTP_CONN
        conn.auto_open = False
        conn.connect()
        conn.send('GET /hello HTTP/1.1')
        conn.send(("Host: %s" % self.HOST).encode('ascii'))
        
        # Wait for our socket timeout
        time.sleep(timeout * 2)
        
        # The conn should have already sent 408.
        response = conn.response_class(conn.sock, method="GET")
        response.begin()
        self.assertEqual(response.status, 408)
        conn.close()
    
    def test_HTTP11_Timeout_after_request(self):
        # If we timeout after at least one request has succeeded,
        # the server will close the conn without 408.
        if cherrypy.server.protocol_version != "HTTP/1.1":
            print "skipped",
            return

        
        self.PROTOCOL = "HTTP/1.1"
        
        # Make an initial request
        self.persistent = True
        conn = self.HTTP_CONN
        conn.putrequest("GET", "/timeout?t=%s" % timeout, skip_host=True)
        conn.putheader("Host", self.HOST)
        conn.endheaders()
        response = conn.response_class(conn.sock, method="GET")
        response.begin()
        self.assertEqual(response.status, 200)
        self.body = response.read()
        self.assertBody(str(timeout))
        
        # Make a second request on the same socket
        conn._output('GET /hello HTTP/1.1')
        conn._output("Host: %s" % self.HOST)
        conn._send_output()
        response = conn.response_class(conn.sock, method="GET")
        response.begin()
        self.assertEqual(response.status, 200)
        self.body = response.read()
        self.assertBody("Hello, world!")
        
        # Wait for our socket timeout
        time.sleep(timeout * 2)
        
        # Make another request on the same socket, which should error
        conn._output('GET /hello HTTP/1.1')
        conn._output("Host: %s" % self.HOST)
        conn._send_output()
        response = conn.response_class(conn.sock, method="GET")
        try:
            response.begin()
        except:
            if not isinstance(sys.exc_info()[1],
                              (socket.error, httplib.BadStatusLine)):
                self.fail("Writing to timed out socket didn't fail"
                          " as it should have: %s" % sys.exc_info()[1])
        else:
            if response.status != 408:
                self.fail("Writing to timed out socket didn't fail"
                          " as it should have: %s" %
                          response.read())
        
        conn.close()
        
        # Make another request on a new socket, which should work
        self.persistent = True
        conn = self.HTTP_CONN
        conn.putrequest("GET", "/", skip_host=True)
        conn.putheader("Host", self.HOST)
        conn.endheaders()
        response = conn.response_class(conn.sock, method="GET")
        response.begin()
        self.assertEqual(response.status, 200)
        self.body = response.read()
        self.assertBody(pov)
        
        # Make another request on the same socket,
        # but timeout on the headers
        conn.send('GET /hello HTTP/1.1')
        # Wait for our socket timeout
        time.sleep(timeout * 2)
        response = conn.response_class(conn.sock, method="GET")
        try:
            response.begin()
        except:
            if not isinstance(sys.exc_info()[1],
                              (socket.error, httplib.BadStatusLine)):
                self.fail("Writing to timed out socket didn't fail"
                          " as it should have: %s" % sys.exc_info()[1])
        else:
            self.fail("Writing to timed out socket didn't fail"
                      " as it should have: %s" %
                      response.read())
        
        conn.close()
        
        # Retry the request on a new connection, which should work
        self.persistent = True
        conn = self.HTTP_CONN
        conn.putrequest("GET", "/", skip_host=True)
        conn.putheader("Host", self.HOST)
        conn.endheaders()
        response = conn.response_class(conn.sock, method="GET")
        response.begin()
        self.assertEqual(response.status, 200)
        self.body = response.read()
        self.assertBody(pov)
        conn.close()
    
    def test_HTTP11_pipelining(self):
        if cherrypy.server.protocol_version != "HTTP/1.1":
            print "skipped ",
            return
        
        self.PROTOCOL = "HTTP/1.1"
        
        # Test pipelining. httplib doesn't support this directly.
        self.persistent = True
        conn = self.HTTP_CONN
        
        # Put request 1
        conn.putrequest("GET", "/hello", skip_host=True)
        conn.putheader("Host", self.HOST)
        conn.endheaders()
        
        for trial in xrange(5):
            # Put next request
            conn._output('GET /hello HTTP/1.1')
            conn._output("Host: %s" % self.HOST)
            conn._send_output()
            
            # Retrieve previous response
            response = conn.response_class(conn.sock, method="GET")
            response.begin()
            body = response.read()
            self.assertEqual(response.status, 200)
            self.assertEqual(body, "Hello, world!")
        
        # Retrieve final response
        response = conn.response_class(conn.sock, method="GET")
        response.begin()
        body = response.read()
        self.assertEqual(response.status, 200)
        self.assertEqual(body, "Hello, world!")
        
        conn.close()
    
    def test_100_Continue(self):
        if cherrypy.server.protocol_version != "HTTP/1.1":
            print "skipped ",
            return
        
        self.PROTOCOL = "HTTP/1.1"
        
        self.persistent = True
        conn = self.HTTP_CONN
        
        # Try a page without an Expect request header first.
        # Note that httplib's response.begin automatically ignores
        # 100 Continue responses, so we must manually check for it.
        conn.putrequest("POST", "/upload", skip_host=True)
        conn.putheader("Host", self.HOST)
        conn.putheader("Content-Type", "text/plain")
        conn.putheader("Content-Length", "4")
        conn.endheaders()
        conn.send("d'oh")
        response = conn.response_class(conn.sock, method="POST")
        version, status, reason = response._read_status()
        self.assertNotEqual(status, 100)
        conn.close()
        
        # Now try a page with an Expect header...
        conn.connect()
        conn.putrequest("POST", "/upload", skip_host=True)
        conn.putheader("Host", self.HOST)
        conn.putheader("Content-Type", "text/plain")
        conn.putheader("Content-Length", "17")
        conn.putheader("Expect", "100-continue")
        conn.endheaders()
        response = conn.response_class(conn.sock, method="POST")
        
        # ...assert and then skip the 100 response
        version, status, reason = response._read_status()
        self.assertEqual(status, 100)
        while True:
            line = response.fp.readline().strip()
            if line:
                self.fail("100 Continue should not output any headers. Got %r" % line)
            else:
                break
        
        # ...send the body
        conn.send("I am a small file")
        
        # ...get the final response
        response.begin()
        self.status, self.headers, self.body = webtest.shb(response)
        self.assertStatus(200)
        self.assertBody("thanks for 'I am a small file' (text/plain)")
        conn.close()
    
    def test_readall_or_close(self):
        if cherrypy.server.protocol_version != "HTTP/1.1":
            print "skipped ",
            return
        
        self.PROTOCOL = "HTTP/1.1"
        
        if self.scheme == "https":
            self.HTTP_CONN = httplib.HTTPSConnection
        else:
            self.HTTP_CONN = httplib.HTTPConnection
        
        # Test a max of 0 (the default) and then reset to what it was above.
        old_max = cherrypy.server.max_request_body_size
        for new_max in (0, old_max):
            cherrypy.server.max_request_body_size = new_max
            
            self.persistent = True
            conn = self.HTTP_CONN
            
            # Get a POST page with an error
            conn.putrequest("POST", "/err_before_read", skip_host=True)
            conn.putheader("Host", self.HOST)
            conn.putheader("Content-Type", "text/plain")
            conn.putheader("Content-Length", "1000")
            conn.putheader("Expect", "100-continue")
            conn.endheaders()
            response = conn.response_class(conn.sock, method="POST")
            
            # ...assert and then skip the 100 response
            version, status, reason = response._read_status()
            self.assertEqual(status, 100)
            while True:
                skip = response.fp.readline().strip()
                if not skip:
                    break
            
            # ...send the body
            conn.send("x" * 1000)
            
            # ...get the final response
            response.begin()
            self.status, self.headers, self.body = webtest.shb(response)
            self.assertStatus(500)
            
            # Now try a working page with an Expect header...
            conn._output('POST /upload HTTP/1.1')
            conn._output("Host: %s" % self.HOST)
            conn._output("Content-Type: text/plain")
            conn._output("Content-Length: 17")
            conn._output("Expect: 100-continue")
            conn._send_output()
            response = conn.response_class(conn.sock, method="POST")
            
            # ...assert and then skip the 100 response
            version, status, reason = response._read_status()
            self.assertEqual(status, 100)
            while True:
                skip = response.fp.readline().strip()
                if not skip:
                    break
            
            # ...send the body
            conn.send("I am a small file")
            
            # ...get the final response
            response.begin()
            self.status, self.headers, self.body = webtest.shb(response)
            self.assertStatus(200)
            self.assertBody("thanks for 'I am a small file' (text/plain)")
            conn.close()
    
    def test_No_Message_Body(self):
        if cherrypy.server.protocol_version != "HTTP/1.1":
            print "skipped ",
            return
        
        self.PROTOCOL = "HTTP/1.1"
        
        # Set our HTTP_CONN to an instance so it persists between requests.
        self.persistent = True
        
        # Make the first request and assert there's no "Connection: close".
        self.getPage("/")
        self.assertStatus('200 OK')
        self.assertBody(pov)
        self.assertNoHeader("Connection")
        
        # Make a 204 request on the same connection.
        self.getPage("/custom/204")
        self.assertStatus(204)
        self.assertNoHeader("Content-Length")
        self.assertBody("")
        self.assertNoHeader("Connection")
        
        # Make a 304 request on the same connection.
        self.getPage("/custom/304")
        self.assertStatus(304)
        self.assertNoHeader("Content-Length")
        self.assertBody("")
        self.assertNoHeader("Connection")
    
    def test_Chunked_Encoding(self):
        if cherrypy.server.protocol_version != "HTTP/1.1":
            print "skipped ",
            return
        
        if (hasattr(self, 'harness') and
            "modpython" in self.harness.__class__.__name__.lower()):
            # mod_python forbids chunked encoding
            print "skipped ",
            return
        
        self.PROTOCOL = "HTTP/1.1"
        
        # Set our HTTP_CONN to an instance so it persists between requests.
        self.persistent = True
        conn = self.HTTP_CONN
        
        # Try a normal chunked request (with extensions)
        body = ("8;key=value\r\nxx\r\nxxxx\r\n5\r\nyyyyy\r\n0\r\n"
                "Content-Type: application/x-json\r\n\r\n")
        conn.putrequest("POST", "/upload", skip_host=True)
        conn.putheader("Host", self.HOST)
        conn.putheader("Transfer-Encoding", "chunked")
        conn.putheader("Trailer", "Content-Type")
        # Note that this is somewhat malformed:
        # we shouldn't be sending Content-Length.
        # RFC 2616 says the server should ignore it.
        conn.putheader("Content-Length", len(body))
        conn.endheaders()
        conn.send(body)
        response = conn.getresponse()
        self.status, self.headers, self.body = webtest.shb(response)
        self.assertStatus('200 OK')
        self.assertBody("thanks for 'xx\r\nxxxxyyyyy' (application/x-json)")
        
        # Try a chunked request that exceeds server.max_request_body_size.
        # Note that the delimiters and trailer are included.
        body = "3e3\r\n" + ("x" * 995) + "\r\n0\r\n\r\n"
        conn.putrequest("POST", "/upload", skip_host=True)
        conn.putheader("Host", self.HOST)
        conn.putheader("Transfer-Encoding", "chunked")
        conn.putheader("Content-Type", "text/plain")
        # Chunked requests don't need a content-length
##        conn.putheader("Content-Length", len(body))
        conn.endheaders()
        conn.send(body)
        response = conn.getresponse()
        self.status, self.headers, self.body = webtest.shb(response)
        self.assertStatus(413)
        self.assertBody("")
        conn.close()
    
    def test_Content_Length(self):
        # Try a non-chunked request where Content-Length exceeds
        # server.max_request_body_size. Assert error before body send.
        self.persistent = True
        conn = self.HTTP_CONN
        conn.putrequest("POST", "/upload", skip_host=True)
        conn.putheader("Host", self.HOST)
        conn.putheader("Content-Type", "text/plain")
        conn.putheader("Content-Length", "9999")
        conn.endheaders()
        response = conn.getresponse()
        self.status, self.headers, self.body = webtest.shb(response)
        self.assertStatus(413)
        self.assertBody("")
        conn.close()
    
    def test_HTTP10(self):
        self.PROTOCOL = "HTTP/1.0"
        if self.scheme == "https":
            self.HTTP_CONN = httplib.HTTPSConnection
        else:
            self.HTTP_CONN = httplib.HTTPConnection
        
        # Test a normal HTTP/1.0 request.
        self.getPage("/page2")
        self.assertStatus('200 OK')
        self.assertBody(pov)
        # Apache, for example, may emit a Connection header even for HTTP/1.0
##        self.assertNoHeader("Connection")
        
        # Test a keep-alive HTTP/1.0 request.
        self.persistent = True
        
        self.getPage("/page3", headers=[("Connection", "Keep-Alive")])
        self.assertStatus('200 OK')
        self.assertBody(pov)
        self.assertHeader("Connection", "Keep-Alive")
        
        # Remove the keep-alive header again.
        self.getPage("/page3")
        self.assertStatus('200 OK')
        self.assertBody(pov)
        # Apache, for example, may emit a Connection header even for HTTP/1.0
##        self.assertNoHeader("Connection")
    
    def test_598(self):
        remote_data_conn = urllib.urlopen('%s://%s:%s/one_megabyte_of_a/' %
                                          (self.scheme, self.HOST, self.PORT,))
        buf = remote_data_conn.read(512)
        time.sleep(timeout * 0.6)
        remaining = (1024 * 1024) - 512
        while remaining:
            data = remote_data_conn.read(remaining)
            if not data:
                break
            else:
                buf += data
            remaining -= len(data)
       
        self.assertEqual(len(buf), 1024 * 1024)
        self.assertEqual(buf, "a" * 1024 * 1024)
        self.assertEqual(remaining, 0)
        remote_data_conn.close()


if __name__ == "__main__":
    setup_server()
    helper.testmain({'server.socket_timeout': timeout,
                     'server.socket_host': '127.0.0.1'})
Tip: Filter by directory path e.g. /media app.js to search for public/media/app.js.
Tip: Use camelCasing e.g. ProjME to search for ProjectModifiedEvent.java.
Tip: Filter by extension type e.g. /repo .js to search for all .js files in the /repo directory.
Tip: Separate your search with spaces e.g. /ssh pom.xml to search for src/ssh/pom.xml.
Tip: Use ↑ and ↓ arrow keys to navigate and return to view the file.
Tip: You can also navigate files with Ctrl+j (next) and Ctrl+k (previous) and view the file with Ctrl+o.
Tip: You can also navigate files with Alt+j (next) and Alt+k (previous) and view the file with Alt+o.