小编Rya*_*ing的帖子

最近升级到OSX Mavericks已经破坏了我的Rails应用程序的数据库连接.

当我尝试从数据库中提取时,服务器返回以下错误:

PG::ConnectionBad (could not connect to server: Connection refused
    Is the server running on host "localhost" (::1) and accepting
    TCP/IP connections on port 5432?
could not connect to server: Connection refused
    Is the server running on host "localhost" (127.0.0.1) and accepting
    TCP/IP connections on port 5432?
could not connect to server: Connection refused
    Is the server running on host "localhost" (fe80::1) and accepting
    TCP/IP connections on port 5432?

当psql我试着跑步时,我得到:

psql: could not connect to server: No …

我有以下型号:

class Section < ActiveRecord::Base
  belongs_to :page
  has_many :revisions, :class_name => 'SectionRevision', :foreign_key => 'section_id'
  has_many :references

  has_many :revisions, :class_name => 'SectionRevision', 
                       :foreign_key => 'section_id'

  delegate :position, to: :current_revision

  def current_revision
    self.revisions.order('created_at DESC').first
  end
end

current_revision最近创建的位置在哪里revision.有可能current_revision变成一个关联,所以我可以执行查询Section.where("current_revision.parent_section_id = '1'")吗？或者我应该current_revision在我的数据库中添加一列而不是尝试虚拟地或通过关联创建它？

我试着在jQuery中获取元素标记名称.

我有以下html:

<div class="section" id="New_Revision">

    <h1>New Revision&nbsp<img alt="Lock_closed" class="edit" data-id="1" src="/assets/lock_closed.svg" /></h1>

    <p>This is a test paragraph.</p>

    <ol class="references">
      <li>test</li>
    </ol>
</div>

和javascript:

$(".edit").click(function(){
    $(this).closest("div.section").children().each(function(){
        alert($(this).tagName + " - " + $(this).html());
    });     
})

我试过$(this).tagName,$(this).nodeName并$(this).attr("tag")在这个问题指出:可提供的jQuery标签的名字吗？

但我总是得到undefined回报.在html()正常输出.为什么我不能获得每个元素的标记名称？

我有以下代码:

$(document).on('keyup', 'p[contenteditable="true"]', function(e) {
    if(e.which == 13) {
        e.preventDefault();
        $(this).after('<p contenteditable = "true"></p>');
        $(this).next('p').focus();
    } else if((e.which == 8 || e.which == 46) && $(this).text() == "") {
        e.preventDefault();
        alert("Should remove element.");
        $(this).remove();
        $(this).previous('p').focus();
    };
});

我想在按下某个键时阻止默认操作.preventDefault适用keypress但不适用keyup.有没有办法防止违法行为$(document).on('keyup')？

我link_to在我的调用update我的控制器中的动作:

<%= link_to((image_tag("lock_closed.svg", :class => "edit")), :controller => "sections", :action => "update",:id => section.id, :remote => true) %>

但我真的想update通过一些普通的图像标签来调用这个动作.

所以类似于:

<%= image_tag("lock_closed.svg", :class => "edit")%>

和:

$(".edit").click(function(){
    if ($(this).hasClass("update")){
    // call update action
    } else {
    //do something else 
    };
})

是否可以通过这种方式调用动作？我一直在使用GET&POST或Ajax方法,但我不知道如何利用它们来定位特定的控制器和动作.

我试图使用箭头键遍历contenteditable段落.我不能在所有段落中放置一个包含div,因为它可能被其他不可编辑的元素划分.

我需要能够确定第一行的字符长度,以便当光标在行上时按下向上箭头键,然后它将跳到上一段 - 希望保持光标相对于行的位置.

我可以用以下方法获取游标索引:

function cursorIndex() {
    return window.getSelection().getRangeAt(0).startOffset;
}

并将其设置为:在此处找到 - Javascript Contenteditable - 将Cursor/Caret设置为索引

var setSelectionRange = function(element, start, end) {
    var rng = document.createRange(),
        sel = getSelection(),
        n, o = 0,
        tw = document.createTreeWalker(element, NodeFilter.SHOW_TEXT, null, null);
    while (n = tw.nextNode()) {
        o += n.nodeValue.length;
        if (o > start) {
            rng.setStart(n, n.nodeValue.length + start - o);
            start = Infinity;
        }
        if (o >= end) {
            rng.setEnd(n, n.nodeValue.length + end - o);
            break;
        }
    }
    sel.removeAllRanges();
    sel.addRange(rng); …

我正在尝试按照如何在GraphQL上的本教程设置一个graphcool订阅/ websockets，但收到以下消息：

WebSocket与“ wss：//subscriptions.graph.cool/v1/###”的连接失败：WebSocket在建立连接之前已关闭。

我似乎已经按照教程掌握了所有内容。您知道为什么未建立websockets连接吗？

index.js

import React from 'react'
import ReactDOM from 'react-dom'
import App from './components/App'
import registerServiceWorker from './registerServiceWorker'
import './styles/index.css'
import { ApolloProvider, createNetworkInterface, ApolloClient } from 'react-apollo'
import { SubscriptionClient, addGraphQLSubscriptions } from 'subscriptions-transport-ws'
import { BrowserRouter } from 'react-router-dom'
import { GC_AUTH_TOKEN } from './constants'

const networkInterface = createNetworkInterface({
  uri: 'https://api.graph.cool/simple/v1/###'
})

const wsClient = new SubscriptionClient('wss://subscriptions.graph.cool/v1/###', {
  reconnect: true,
  connectionParams: {
     authToken: localStorage.getItem(GC_AUTH_TOKEN),
  }
})

const networkInterfaceWithSubscriptions = addGraphQLSubscriptions(
  networkInterface,
  wsClient …

我有一个Page包含许多Section模型的模型,它与一个SectionRevision通过相关联current_revision.从Page模型我想选择所有Sections在current_revision.parent_section_id不为零.

Section 模型:

class Section < ActiveRecord::Base
  belongs_to :page
  has_many :revisions, :class_name => 'SectionRevision', :foreign_key => 'section_id'
  has_many :references

  has_many :revisions, :class_name => 'SectionRevision', 
                       :foreign_key => 'section_id'
  belongs_to :current_revision, :class_name => 'SectionRevision', :foreign_key => 'current_revision_id'

  delegate :position, to: :current_revision

  def set_current_revision
    self.current_revision = self.revisions.order('created_at DESC').first
  end

  def children
    Section.includes(:current_revision).where(:section_revisions => {:parent_section_id => self.id})
  end
end

和Page型号:

class Page < ActiveRecord::Base
  belongs_to :parent, :class_name => …

我将如何修改它(如何在contenteditable元素(div)中设置插入符号(光标)？)所以它接受一个数字索引和元素并将光标位置设置为该索引？

例如:如果我有段落:

<p contenteditable="true">This is a paragraph.</p>

我打电话给:

setCaret($(this).get(0), 3)

光标将移动到索引3,如下所示:

Thi|s is a paragraph.

我有这个,但没有运气:

function setCaret(contentEditableElement, index)
{
    var range,selection;
    if(document.createRange)//Firefox, Chrome, Opera, Safari, IE 9+
    {
        range = document.createRange();//Create a range (a range is a like the selection but invisible)
        range.setStart(contentEditableElement,index);
        range.collapse(true);
        selection = window.getSelection();//get the selection object (allows you to change selection)
        selection.removeAllRanges();//remove any selections already made
        selection.addRange(range);//make the range you have just created the visible selection
    }
    else if(document.selection)//IE 8 and lower
    { …

我试图在悬停时将图像从50%灰度滤镜转换为无滤镜状态.

但转换在Firefox中不起作用.是否有可能只使用css在firefox中运行转换？

img {
    filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'saturate\' values=\'0.5\'/></filter></svg>#grayscale"); /* Firefox 3.5+ */
    filter: gray alpha(opacity=50); /* IE6-9 */
    -webkit-filter: grayscale(50%); /* Chrome 19+ & Safari 6+ */
    -webkit-transition: all .6s ease; /* Fade to color for Chrome and Safari */
    -moz-transition: all .6s ease; 
    -ms-transition: all .6s ease; 
    transition: all .6s ease;
    -webkit-backface-visibility: hidden; /* Fix for transition flickering */
}
img:hover {
    filter: none;
    -webkit-filter: grayscale(0);
}