Sencha Cmd 进阶

This guide covers capabilities of Sencha Cmd available to advanced users.

Prerequisites

The following guides are recommended reading before proceeding further:

• Sencha Cmd 介绍.
• Using Sencha Cmd.

Installation Considerations

Location

The Installer lets you select a destination path, but changing this can have side effects (see the section “Multiple Installed Versions”). Ideally, all versions of Sencha Cmd are installed in a single base folder with sub-folders named by the version number. On Windows, the default install folder for a single-user installation looks like this:

C:\Users\myself\bin\Sencha\Cmd\n.n.n.n\

If you change this path, preserve the version number folder as well as installing any other versions of Sencha Cmd in that same parent folder.

Multiple Installed Versions

At the command prompt, all calls to sencha go to the most recently installed version of Sencha Cmd. Sometimes this version may not be compatible with the current application. For example, if an application required Sencha Cmd 5.1.3.61 specifically for some reason, you can adjust the PATH for a console/terminal as shown below.

On Windows, this looks like this (n is the current version):

set PATH=C:\Users\Me\bin\Sencha\Cmd\5.1.3.61;%PATH%
sencha ....

On OS X and Linux, this looks like this:

set PATH=~/bin/Sencha/Cmd/5.1.3.61:$PATH
sencha ....

With the above adjustments, sencha will route to the desired version for the current console or terminal.

Configuration

Any parameter that can be passed to Sencha Cmd on the command line can be set as a configuration option in one of the configuration files discussed below. If you know the command line option, it is a simple matter to add that option to a configuration file.

For example, to specify the ignore parameter for sencha compile in the configuration, add this line:

sencha.compile#ignore=attic

This particular setting is not necessarily a recommended practice, but it just serves to illustrate the syntax. The parts of the command that goes before the # are the Sencha Cmd commands separated by dots. Following the # is the option name.

To set global options (like debug logging), do this:

sencha#debug=true

Configuration becomes more important over time as Sencha Cmd (especially the compiler) evolves.

To see the current configuration properties, run this command:

sencha diag show

Configuration Files

Similar to Apache Ant (on which many aspects of Sencha Cmd are based), configuration is applied in a “first-write-wins” model. This is essential to allow property values to be overridden by the command line.

The process of loading configuration begins by searching from the current directory and proceeds up the file system until the Workspace is found. Along the way, Sencha Cmd looks for the presence of an application or Sencha Framework SDK. At the end of the loading process, Sencha Cmd loads any of the following files it detects in this order:

• ${app.dir}/app.json - Application configuration when in an application folder that is the most specific loads first.
• ${app.dir}/.sencha/app/sencha.cfg - Application configuration when in an application folder that is the most specific loads first.
• ${package.dir}/package.json - Package configuration when in a package folder that is the most specific loads next.
• ${package.dir}/.sencha/package/sencha.cfg - Package configuration when in a package folder that is the most specific loads next.
• ${workspace.dir}/workspace.json - Workspace configuration applies next when you are in a workspace (or an app or package in the workspace).
• ${workspace.dir}/.sencha/workspace/sencha.cfg - Workspace configuration applies next when you are in a workspace (or an app or package in the workspace).
• ${framework.dir}/cmd/sencha.cfg - Based on the applicable framework for the app or package at the current directory, those properties load next.
• ${home.dir}/.sencha/cmd/sencha.cfg - Your personal configuration loads next. This typically only sets high-level properties.
• ${cmd.dir}/../sencha.cfg - Local machine Sencha Cmd configuration loads next. This typically only sets high-level properties. This loads from the parent folder of the running Sencha Cmd, which is the folder that holds the various installed versions of Sencha Cmd.
• ${cmd.dir}/sencha.cfg - Lastly, the Sencha Cmd, version specific configuration loads.

The most important configuration properties are those passed on the command line. These will override properties coming from any of the above files. For example:

sencha config -prop foo=42 then ...

This sets “foo” to 42 prior to the loading the config files, and in Sencha Cmd v3.1 and later, this setting “wins”.

In most cases you can tell where a property comes from by its prefix:

• app. – See "app.json" and ".sencha/app/sencha.cfg".
• package. – See "package.json" and ".sencha/package/sencha.cfg".
• workspace. – See "workspace.json" and ".sencha/workspace/sencha.cfg".
• framework. – See "cmd/sencha.cfg" in the Ext JS or Sencha Touch SDK.
• cmd. – See "sencha.cfg" in the Sencha Cmd install folder.

It is not required that these properties be set in these files, but it is the default and following this convention will help you manage these settings. That said, there are times when a Workspace setting may need to be overridden by an application. To do this, the workspace.foo property must be set in ".sencha/app/sencha.cfg" because that is the application-level configuration file. When deviating from the convention, leaving behind a comment would be advised.

Use of JSON Descriptors

Starting in Sencha Cmd 5, JSON files are now always respected as higher priority than their corresponding "sencha.cfg" file. Previously this was only true for applications based on Sencha Touch.

The content of files like "app.json", "package.json" and "workspace.json" are flattened into properties with the filename prefix applied ("app", "package" or "workspace"). For example, if you placed the following JSON object in "workspace.json":

{
    "foo": {
        "bar": 42
    }
}

This would set the workspace.foo.bar property to the value “42”.

This mechanism is what allows the app.id property to be imported from "app.json" for use in the build process.

Java System Properties

Java System Properties may need to be set for Sencha Cmd, such as HTTP Proxy Server settings. The "sencha.cfg" file in your Cmd install folder has default settings for proxies that enable detection of your system-defined proxy. For further information, consult the comments found in "${cmd.dir}/sencha.cfg".

NOTE: If you need to change any of these settings, use the "${cmd.dir}/../sencha.cfg" file so that these settings are preserved across Cmd upgrades.

These properties effect Sencha Cmd’s ability to access the Web to perform sencha upgrade or to download packages. These options are in Cmd v3.1.1 and later.

Command Line Details

These tricks help if you make frequent use of Sencha Cmd.

Shortest Unique Prefix

All commands, categories and options in Sencha Cmd can be specified by their full name or by the shortest prefix that is unique.

To illustrate, since generate is the only top-level category in Sencha Cmd that currently starts with the letter “g”, and likewise, app is the only command in that category that starts with an “a”, the following commands are equivalent:

sencha generate app MyApp ../MyApp
sencha gen ap MyApp ../MyApp

Important While this can be convenient at the console or terminal, it is not a good practice to use extremely short/terse prefixes in scripts. The use of terse commands in scripts makes it hard to understand or maintain the script, and can break if new commands make the short form ambiguous.

Command Chaining

The Sencha Cmd command line processor executes all commands given to it until they have all been dispatched. This means you can avoid the cost of relaunching the Sencha Cmd process to execute multiple commands. To take advantage of this, insert and or then between commands.

The and and then commands are based on the execution model of Sencha Cmd and its hierarchical structure of commands and categories. The and command is used to execute another command in the same category as the previous command. This is the most common use case.

For example, to generate a controller and two models, use this:

cd /path/to/MyApp
sencha generate controller Central and model User id:int and model Ticket id,name,email

In the above, the two uses of and caused two generate model commands to be executed. The then command is similar to and, except that the next command will be part of the root category (that is, the sencha command).

For example, the following generates a new model, then builds the application:

cd /path/to/MyApp
sencha generate model User id:int,name then app build

Response Files

When command chaining starts to make command lines too long to be readable, perhaps in a complex build script, you can put command line arguments in a file and tell Sencha Cmd to read arguments from that file.

For example:

cd /path/to/MyApp
sencha @file.sencha

In the above, the "file.sencha" file is read and each line is taken to be a command line argument, unless that line begins with “#”, in which case it is skipped. All lines from the specified file are inserted into the command line arguments as if they had been typed there instead of "@file.sencha". This means that "file.sencha" can contain response file insertions as well (for example, "@file2.sencha").

Category State

For performance reasons, some categories maintain state across multiply executed commands. The best example of this is the new compile category of commands. Instead of reading all the sources for each command, the compile category maintains a cache of all the files in the class path. This context is then available to all of the commands in the category.

The following command rebuilds the ext-all-dev.js and ext-all.js files while reading the framework sources only once:

cd /path/to/MyApp
sencha compile -c sdk/src --debug=true concat -o sdk/ext-all-dev.js \
    and --debug=false concat -c -o sdk/ext-all.js

If you don’t want to use this caching, perhaps because the set of files is not the same for the next set of outputs, use the then command, like this:

cd /path/to/MyApp
sencha compile -c sdk/src --debug=true concat -o sdk/ext-all-dev.js \
     then compile -c app/foo --debug=true concat -o app/foo/foo-all.js

At present, only the compile category maintains state across commands.

Plugins

While the same Sencha Cmd install is used by both Ext JS and Sencha Touch, there are many times when commands perform slightly different operations depending on the framework. Further, some commands may only be available for one framework.

To accommodate this, the functionality of Sencha Cmd is partitioned across two layers: the command line (properly called “Sencha Cmd”) and the lower-level interface for use in Ant. Commands that have these special concerns are routed from the command line into a plugin.

A Sencha Cmd plugin is just an Ant script contained in a file called "plugin.xml" though for any given command, executed in an application or workspace, there are potentially several active plugins.

The process begins by looking for the most specific plugin available as follows:

• ${app.dir}/.sencha/app/plugin.xml
• ${workspace.dir}/.sencha/workspace/plugin.xml
• ${cmd.dir}/plugins/${framework.name}/${framework.plugin.version}/plugin.xml
• ${cmd.dir}/plugin.xml (also known as the "default plugin")

The first of these to be found is based on the current directory. Sencha Cmd then loads only that plugin and invokes specific targets based on the command it was given. These plugins, however, contain the Ant invocation required to load the plugin at the next level up. For example, if the application plugin is found, it contains an import of the workspace plugin. That plugin contains an import of the framework plugin and, lastly, that contains an import of the default plugin.

Extension Points

Technically, the lowest two levels (the framework and default plugins) are the only plugins that contain actual code. The application and workspace plugins are empty by default but are present to allow for user extension of these built-in commands. The purpose for this is to allow you to add logic to enforce project or application standards for code generation requests made to Sencha Cmd.

If you want to check to see if new model definitions follow project guidelines, for example, the first field is always id:string, add this to the application or workspace "plugins.xml":

<target name="-before-generate-model">
    <if>
        <not><matches string="${args.fields}" pattern="^id\:string,.*"/></not>
        <then>
            <fail>Models must have "id:string" as first field.</fail>
        </then>
    </if>
</target>

Similarly you can also provide a hook to update other systems when a new model has been added.

<target name="-after-generate-model">
    ... post new/updated Model ${args.name} and ${args.fields} ...
</target>

The actual target names differ by which plugin you extend. For specifics, consult the comments in the respective "plugin.xml" file.

Note. The default "plugin.xml" file imports Ant Contrib which provides many useful tasks.

Use in Ant

While the primary use of Sencha Cmd is at the command line (hence its name), Sencha Cmd is also usable directly from Ant. For details about the many commands provided at this level, see the Ant 集成 guide.

Next Steps

• Ant 集成
• Sencha Cmd 包(Packages)
• Sencha 编译器 参考