使用predis它可以检查密钥是否存在？
我的users数据存储如下：
public function createUser($email, $password, $username)
{
return $this->predis->hMset("user:{$username}", [
'email' => $email,
'password' => $password,
'username' => $username
]);
}
现在，当我检查用户是否存在时，请执行以下操作：
public function checkUserExists($username)
{
return $this->predis->hExists("user:{$username}", 'username');
}
是否可以检查用户是否存在而不必检查密钥是否存在？例如，仅检查user:{$username}？
是否可以输出stdout到文件，但忽略stderr？
我有一个 Python 脚本，用于sys.stderr.write(error)将错误输出到stderr. 对于这个特定的脚本，我想忽略这些。这怎么可能？
这是 crontab 中的当前条目：
* * * * * /Users/me/bin/scrape-headlines /Users/me/proxies.txt >> /Users/me/headlines.txt 2>&1
scrape-headlines是一个调用Python脚本的bash脚本。
我不能用@computed。如果我在下面运行我的代码，我会收到一个错误：
Uncaught TypeError: An element descriptor's .kind property must be either "method" or "field", but a decorator created an element descriptor with .kind "undefined"
at _toElementDescriptor (app.js:46281)
at _toElementFinisherExtras (app.js:46283)
at _decorateElement (app.js:46273)
at app.js:46269
at Array.forEach (<anonymous>)
at _decorateClass (app.js:46269)
at _decorate (app.js:46251)
at Module../src/App/stores/UserStore.js (app.js:46301)
at __webpack_require__ (bootstrap:19)
at Module../src/App/stores/index.js (index.js:1)
这是我的UserStore.js文件：
import {
configure,
runInAction,
observable,
action,
computed
} from 'mobx'
import API from '../api'
configure({ enforceActions: 'observed' })
class UserStore {
@observable …我跑了docker-compose -f docker-compose.prod.yml up，我立即得到错误：
ERROR: for frontend Cannot start service frontend: OCI runtime create failed: container_linux.go:348: starting container process caused "process_linux.go:402: container init caused \"rootfs_linux.go:58: mounting \\\"/c/Users/James/Projects/mysite/frontend/conf/nginx/mysite.template\\\" to rootfs \\\"/var/lib/docker/aufs/mnt/e7a2a699ae3e9ede0dd60b7cfdebb7f2d3adf71e8175157f3c9e88d3285796d2\\\" at \\\"/var/lib/docker/aufs/mnt/e7a2a699ae3e9ede0dd60b7cfdebb7f2d3adf71e8175157f3c9e88d3285796d2/etc/nginx/conf.d/default.conf\\\" caused \\\"not a directory\\\"\"": unknown: Are you trying to mount a directory onto a file (or vice-versa)? Check if the specified host path exists and is the expected type
我的mysite.template文件存在。我正在使用Digital Ocean docker-machine。在开发中，我没有在同一OS（ubuntu 16）上运行此问题。我在Windows上使用docker工具箱进行开发。
这是来自的前端配置docker-compose.prod.yml：
frontend:
image: nginx:stable-alpine
restart: always
networks:
- …我正在学习汇编 (NASM) 并使用 Linux 系统调用。
我在使用以下代码时遇到问题。我正在尝试打电话sys_mkdir。应创建一个目录“Hello World”。但是，它正在创建以下Hello World?asmtest??. 为什么是这样？如何title包含以及如何删除?.
SECTION .data
msg: db "Hello World", 10
len: equ $-msg
title: db "asmtest", 7
mode: dd 755
SECTION .text
global main
main:
; Make a directory
mov ecx,mode
mov ebx,msg
mov eax,39
int 0x80
; Print Hello World to screen
mov edx,len
mov ecx,msg
mov ebx,1
mov eax,4
int 0x80
; Exit
mov ebx,0
mov eax,1
int 0x80
我不知道如何在主题中更好地描述我的问题......
我有一个看起来像这样的表:
$sql = "CREATE TABLE games (
id INT(5) AUTO_INCREMENT PRIMARY KEY,
name VARCHAR (255),
player_1_id INT (3),
player_1_status BOOLEAN,
player_2_id INT (3),
player_2_status BOOLEAN,
player_3_id INT (3),
player_3_status BOOLEAN
)"
我需要一个像这样的查询:
$stmt = $this->connection->prepare("
SELECT id, name, turn
FROM games
WHERE player_1_id = :value1
OR player_2_id = :value1
OR player_3_id = :value1
");
但另外,我想选择列"player_x_status",具体取决于找到的"player_x_id"等于:value1.我真的不知道如何更好地描述我的问题,这里缺乏条款.
有人可以建议吗？
我正在使用Teensy处理USB MIDI控制器.控制器是一排7个按钮,每个按钮是一个渐进度,7个按钮构成和弦进程.按下时,设备发送MIDI音符开/关消息以播放和弦.
在我的代码中,我有间隔存储在enum:
/*
* Intervals
*/
typedef enum {
ROOT = 0,
UNISON = 0,
DIMINISHED_SECOND = 0,
MINOR_SECOND = 1,
AUGMENTED_UNISON = 1,
HALFSTEP = 1,
MAJOR_SECOND = 2,
DIMINISHED_THIRD = 2,
WHOLESTEP = 2,
MINOR_THIRD = 3,
AUGMENTED_SECOND = 3,
MAJOR_THIRD = 4,
DIMINISHED_FOURTH = 4,
PERFECT_FOURTH = 5,
AUGMENTED_THIRD = 5,
DIMINISHED_FIFTH = 6,
AUGMENTED_FOURTH = 6,
PERFECT_FIFTH = 7,
DIMINISHED_SIXTH = 7,
MINOR_SIXTH = 8,
AUGMENTED_FIFTH = 8,
MAJOR_SIXTH = 9, …我正在使用名为Nuklear的仅标头库。这是仅标头的库。使用来自不同文件的多个包含项时遇到麻烦。它返回一个多定义示例：
...
obj/main.o:main.c:(.text+0x4a52b): multiple definition of `nk_sdl_font_stash_begin'
obj/components.o:components.c:(.text+0x4a56f): first defined here
obj/main.o:main.c:(.text+0x4a563): multiple definition of `nk_sdl_font_stash_end'
obj/components.o:components.c:(.text+0x4a5a7): first defined here
obj/main.o:main.c:(.text+0x4a5f4): multiple definition of `nk_sdl_handle_event'
obj/components.o:components.c:(.text+0x4a638): first defined here
obj/main.o:main.c:(.text+0x4ac9f): multiple definition of `nk_sdl_shutdown'
obj/components.o:components.c:(.text+0x4ace3): first defined here
我试图将库包含到2个文件中。
main.c
#define SDL_MAIN_HANDLED
#include <GL/glew.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_opengl.h>
#define NK_INCLUDE_FIXED_TYPES
#define NK_INCLUDE_STANDARD_IO
#define NK_INCLUDE_STANDARD_VARARGS
#define NK_INCLUDE_DEFAULT_ALLOCATOR
#define NK_INCLUDE_VERTEX_BUFFER_OUTPUT
#define NK_INCLUDE_FONT_BAKING
#define NK_INCLUDE_DEFAULT_FONT
#define NK_IMPLEMENTATION
#define NK_SDL_GL3_IMPLEMENTATION
#include "nuklear.h"
#include "nuklear_sdl_gl3.h"
#include "components.h"
...
components.c
#define SDL_MAIN_HANDLED
#include <GL/glew.h> …我正在关注文档，mobx-react-router但是尝试运行我的应用程序时，在浏览器中出现以下错误：
Uncaught TypeError: An element descriptor's .kind property must be either "method" or "field", but a decorator created an element descriptor with .kind "undefined"
at _toElementDescriptor (app.js:49988)
at _toElementFinisherExtras (app.js:49990)
at _decorateElement (app.js:49980)
at app.js:49976
at Array.forEach (<anonymous>)
at _decorateClass (app.js:49976)
at _decorate (app.js:49958)
at Module../src/App/UserStore.js (app.js:50012)
at __webpack_require__ (bootstrap:19)
at Module../src/index.js (index.js:1)
这是我初始化的方式：
const appContainer = document.getElementById('app');
if(appContainer) {
const browserHistory = createBrowserHistory()
const routingStore = new RouterStore();
const stores = {
users: userStore,
routing: routingStore
} …我正在使用java.net.URL,但我收到了MalformedURLException.我试过查看文档,但我看不出我做错了什么.
下面是按下按钮时触发的代码示例.
public class DownloadController {
public void downloadResource() {
URL obj = new URL("http://www.example.com/docs/resource1.html");
}
}
我究竟做错了什么？我正在使用IntelliJ.没有更多的代码可以显示,上面的代码实际上是控制器.我刚刚开始研究它.