小编Cod*_*bit的帖子

我正在使用scrapy来获取数据,我想使用flask web框架在网页中显示结果.但我不知道如何在烧瓶应用程序中调用蜘蛛.我试图用来CrawlerProcess调用我的蜘蛛,但是我得到了这样的错误:

ValueError
ValueError: signal only works in main thread

Traceback (most recent call last)
File "/Library/Python/2.7/site-packages/flask/app.py", line 1836, in __call__
return self.wsgi_app(environ, start_response)
File "/Library/Python/2.7/site-packages/flask/app.py", line 1820, in wsgi_app
response = self.make_response(self.handle_exception(e))
File "/Library/Python/2.7/site-packages/flask/app.py", line 1403, in handle_exception
reraise(exc_type, exc_value, tb)
File "/Library/Python/2.7/site-packages/flask/app.py", line 1817, in wsgi_app
response = self.full_dispatch_request()
File "/Library/Python/2.7/site-packages/flask/app.py", line 1477, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/Library/Python/2.7/site-packages/flask/app.py", line 1381, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/Library/Python/2.7/site-packages/flask/app.py", line 1475, in full_dispatch_request
rv = self.dispatch_request() …

我尝试将一些文件推送到Github，总大小只有22.2M。我不知道为什么它在总行之后卡住了。我读过Git 推送在推送到 Github 时挂起？并尝试了每个答案，但它根本不起作用。效果好吗？我有什么方法可以加速这个过程吗？

Counting objects: 203, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (176/176), done.
Writing objects: 100% (203/203), 22.12 MiB | 15.70 MiB/s, done.
Total 203 (delta 23), reused 0 (delta 0)

阅读此问题后如何使用 boto3 SSH 并在 EC2 中运行命令？ 我尝试使用SSM在 EC2 实例上自动运行命令。但是，当我写这样的代码时

def excute_command_on_instance(client, command, instance_id):
    response = client.send_command(
        DocumentName="AWS-RunShellScript", # One of AWS' preconfigured documents
        Parameters={'commands': command},
        InstanceIds=instance_id,
    )
    return response

# Using SSM in boto3 to send command to EC2 instances.
ssm_client = boto3.client('ssm')
commands = ['echo "hello world']
instance_id = running_instance[0:1]
excute_command_on_instance(ssm_client, commands, instance_id)

这让我想起

botocore.exceptions.ClientError: An error occurred (AccessDeniedException) when calling the SendCommand operation: User: arn:aws:iam::62771xxxx946:user/Python_CloudComputing is not authorized to perform: ssm:SendCommand on resource: arn:aws:ec2:eu-west-2:6277xxxx3946:instance/i-074f862c3xxxxfc07 . …

我已经阅读了scrapy -1.0.4关于如何以编程方式运行多个蜘蛛的官方文档。它提供了一种方法来做到这一点Crawler Runner，所以我在我的 Flask 应用程序中使用它。但是有一个问题，我想将一个参数传递Crawler给的一部分Start Urls。我不知道该怎么做。这是我的 Flask 应用程序代码：

app.route('/search_process', methods=['GET'])
def search():
    configure_logging()
    runner = CrawlerRunner()
    runner.crawl(EPGDspider)
    # runner.crawl(GDSpider)
    d = runner.join()
    d.addBoth(lambda _: reactor.stop())

    reactor.run()
    return redirect(url_for('details'))

这是我的蜘蛛代码：

__author__ = 'Rabbit'
import scrapy
from scrapy.selector import Selector
from scrapy import Request
from scrapy import Item, Field

class EPGD(Item):

    genID = Field()
    genID_url = Field()
    taxID = Field()
    taxID_url = Field()
    familyID = Field()
    familyID_url = Field()
    chromosome = Field()
    symbol = …

我试图找出与内存模型相关的这三种问题之间的区别。

如果我想模拟一个memory leak场景，我可以创建一个指针，而不调用相应的删除方法。

int main() {
    // OK
    int * p = new int;
    delete p; 

    // Memory leak
    int * q = new int;
    // no delete
}

如果我想模拟一个double free场景，我可以释放一个指针两次，这部分内存稍后将被分配两次。

a = malloc(10);     // 0xa04010
b = malloc(10);     // 0xa04030
c = malloc(10);     // 0xa04050

free(a);
free(b);  // To bypass "double free or corruption (fasttop)" check
free(a);  // Double Free !!

d = malloc(10);     // 0xa04010
e = malloc(10);     // 0xa04030
f = malloc(10);     // …

我是蟒蛇和scrapy的新手.我使用了这个博客中的方法以编程方式运行多个scrapy spiders在一个烧瓶应用程序中运行我的蜘蛛.这是代码:

# list of crawlers
TO_CRAWL = [DmozSpider, EPGDspider, GDSpider]

# crawlers that are running 
RUNNING_CRAWLERS = []

def spider_closing(spider):
    """
    Activates on spider closed signal
    """
    log.msg("Spider closed: %s" % spider, level=log.INFO)
    RUNNING_CRAWLERS.remove(spider)
    if not RUNNING_CRAWLERS:
        reactor.stop()

# start logger
log.start(loglevel=log.DEBUG)

# set up the crawler and start to crawl one spider at a time
for spider in TO_CRAWL:
    settings = Settings()

    # crawl responsibly
    settings.set("USER_AGENT", "Kiran Koduru (+http://kirankoduru.github.io)")
    crawler = Crawler(settings)
    crawler_obj …

我已经阅读了mongodb的文档，并且知道如果我想进行文本搜索，应该使用create index。但是我可以在插入过程中为每个数据创建索引吗？如果可以，该怎么办？

这篇文章中接受的答案Changing border color in mat-form-field介绍了如何更改 的边框线颜色mat-form-field。我想知道是否有办法在聚焦时改变边框颜色。我尝试将以下代码添加到scss文件中，但它不起作用：

.mat-focused .mat-form-field-appearance-outline .mat-form-field-outline-thick {
  /*change color of label*/
  color: green!important;
}

有人能告诉是否有办法改变焦点边框线颜色吗？

我正在学习子结构类型系统，Rust是一个很好的例子。

数组在Rust中是可变的，可以访问多次，而不是只能访问一次。“值读取”，“参考读取”和“可变参考读取”之间有什么区别？我编写了如下程序，但出现了一些错误。

fn main() {
    let xs: [i32; 5] = [1, 2, 3, 4, 5];
    println!("first element of the array: {}", xs[1]);
    println!("first element of the array: {}", &xs[1]);
    println!("first element of the array: {}", &mut xs[1]);
}

这是错误消息：

fn main() {
    let xs: [i32; 5] = [1, 2, 3, 4, 5];
    println!("first element of the array: {}", xs[1]);
    println!("first element of the array: {}", &xs[1]);
    println!("first element of the array: {}", &mut xs[1]);
}