所需输出
输入:使用 OpenCV 或来自 REST 相机 URL 的相机源。 (不关心这个问题)
输出:在进行一些 OpenCV 处理后流式传输 jpeg 图像
到目前为止，我已经基于Falcon做了以下工作tutorial
输入:作为 POST 请求的图像文件
输出:GET 请求端点以及图像的路径
import mimetypes
import os
import re
import uuid
import cv2
import io
import falcon
from falcon import media
import json
import msgpack
class Collection(object):
def __init__(self, image_store):
self._image_store = image_store
def on_get(self, req, resp):
# TODO: Modify this to return a list of href's based on
# what images are actually available.
doc = {
'images': [
{
'href': '/images/1eaf6ef1-7f2d-4ecc-a8d5-6e8adba7cc0e.png'
}
]
}
resp.data = msgpack.packb(doc, use_bin_type=True)
resp.content_type = falcon.MEDIA_MSGPACK
resp.status = falcon.HTTP_200
def on_post(self, req, resp):
name = self._image_store.save(req.stream, req.content_type)
# Unnecessary Hack to read the saved file in OpenCV
image = cv2.imread("images/" + name)
new_image = do_something_with_image(image)
_ = cv2.imwrite("images/" + name, new_image)
resp.status = falcon.HTTP_201
resp.location = '/images/' + name
class Item(object):
def __init__(self, image_store):
self._image_store = image_store
def on_get(self, req, resp, name):
resp.content_type = mimetypes.guess_type(name)[0]
resp.stream, resp.stream_len = self._image_store.open(name)
class ImageStore(object):
_CHUNK_SIZE_BYTES = 4096
_IMAGE_NAME_PATTERN = re.compile(
'[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}\.[a-z]{2,4}$'
)
def __init__(self, storage_path, uuidgen=uuid.uuid4, fopen=io.open):
self._storage_path = storage_path
self._uuidgen = uuidgen
self._fopen = fopen
def save(self, image_stream, image_content_type):
ext = mimetypes.guess_extension(image_content_type) # Issue with this code, Not returning the extension so hard coding it in next line
ext = ".jpg"
name = '{uuid}{ext}'.format(uuid=self._uuidgen(), ext=ext)
image_path = os.path.join(self._storage_path, name)
with self._fopen(image_path, 'wb') as image_file:
while True:
chunk = image_stream.read(self._CHUNK_SIZE_BYTES)
if not chunk:
break
image_file.write(chunk)
return name
def open(self, name):
# Always validate untrusted input!
if not self._IMAGE_NAME_PATTERN.match(name):
raise IOError('File not found')
image_path = os.path.join(self._storage_path, name)
stream = self._fopen(image_path, 'rb')
stream_len = os.path.getsize(image_path)
return stream, stream_len
def create_app(image_store):
api = falcon.API()
api.add_route('/images', Collection(image_store))
api.add_route('/images/{name}', Item(image_store))
api.add_sink(handle_404, '')
return api
def get_app():
storage_path = os.environ.get('LOOK_STORAGE_PATH', './images')
image_store = ImageStore(storage_path)
return create_app(image_store)
响应是这样的:
HTTP/1.1 201 Created
Connection: close
Date: Mon, 03 Dec 2018 13:08:14 GMT
Server: gunicorn/19.7.1
content-length: 0
content-type: application/json; charset=UTF-8
location: /images/e69a83ee-b369-47c3-8b1c-60ab7bf875ec.jpg
上面的代码有两个问题:
- 我首先获取数据流并将其保存在文件中，然后在 OpenCV 中读取它以执行一些其他操作，这相当过分，应该很容易修复，但我不知道如何
- 此服务不传输 JPG。我有一个 GET 请求 url，我可以在浏览器中打开它来查看不理想的图像
那么，如何将 req.stream 数据读取为 numpy 数组？更重要的是，我需要进行哪些更改才能从该服务流式传输图像？
P.S. Apologies for a long post
最佳答案
我找到了一个非常有效的解决方案。有关此方面的更多信息，请查看 this beautiful code .
def gen(camera):
while True:
image = camera.get_frame()
new_image = do_something_with_image(image)
ret, jpeg = cv2.imencode('.jpg', new_image)
yield (b'--frame\r\n'
b'Content-Type: image/jpeg\r\n\r\n' + jpeg.tobytes() + b'\r\n\r\n')
class StreamResource(object):
def on_get(self, req, resp):
labeled_frame = gen(VideoCamera())
resp.content_type = 'multipart/x-mixed-replace; boundary=frame'
resp.stream = labeled_frame
def get_app():
api = falcon.API()
api.add_route('/feed', StreamResource())
return api
关于python-3.x - 如何使用 falcon 服务器流式传输视频(motion jpeg)？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/53595351/