如何使用falcon服务器流式传输视频(运动jpeg)

Question

所需输出

输入：使用OpenCV或REST相机url的相机馈送(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，我已经根据Falcon教程完成了以下操作

输入：图像文件作为POST请求

输出：带有图像路径的GET请求端点

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)

反应是这样的：

HTTP/1.1 201创建

连接：关闭

日期：2018年12月3日星期一13:08:14 GMT

服务器：gunicorn/19.7.1

内容长度：0

内容类型：application/json；charset=UTF-8

位置：/images/e69a83ee-b369-47c3-8b1c-60ab7bf875ec.jpg

以上代码有2个问题：

1. 我首先获取数据流并将其保存在一个文件中，然后在OpenCV中读取它以进行一些其他操作，这是非常过分的，应该很容易修复，但我不知道如何修复
2. 此服务不流式传输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，我需要对该服务的流式图像进行哪些更改？

p.S.为发布后过长道歉

Answer 1

我找到了一个运行良好的解决方案。要了解更多信息，请查看此美丽的代码。

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'--framern'
b'Content-Type: image/jpegrnrn' + jpeg.tobytes() + b'rnrn')

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