OpenAPI is the name of the specification created by the OpenAPI Initiative, an organization that aims to standardize methods for writing APIs.

openapi-generator is a tool that generates a corresponding programming code template based on the design document conforming to OpenAPI, which is currently being created by volunteers due to various circumstances.

Please see the following document and prepare the file, ~/.config/containers/storage.conf, to use the podman command.

We have registered the package on github.com to start the work. Create a working directory (docker-sccp-sinatra-sample) at an arbitrary location with the following command.

If you would like to use your own PC, please install the openapi-generator-cli command based on the official guide.

If your command name is different, such as "openapi-generator", please modify the command name of your Makefile by hand.

If you use the macOS, the bundled ruby command seems to be too old. Please update the ruby command by homebrew as follows.

If the contents of GitHub are updated during the course of the exercise, or if you want to bring the contents of the directory created by git clone up to date, execute the following command.

It won’t work in any meaningful way, but you can check what it does anyway. First, run the command as follows: make sure you are in the docker-sccp-sinatra-sample/ directory before proceeding.

If you just enter the command as "make run", the port number will be a random number between 5000 and 9999. Please use it to avoid port number conflicts when sharing with multiple people.

Next, start a web browser, display the URL, http://localhost:8080/search , and verify that one line of the result is displayed.

You can see the following message in the browser.

At this point, stop the execution of the make run command by pressing Ctrl-c or something similar.

Makefile describes the actual process (a list of commands) corresponding to make gen-code or make run.

The code corresponding to the make gen-code and make run in the Makefile is as follows.

The code corresponding to run in code/Makefile (_docker/Makefile) is a bit simpler, but somewhat more complex.

If you run make run, the same process as if you had run make bundle-install will be performed before processing the body.

This allows you to separate the preparation of necessary library files, etc. and the execution of the program, while writing them as a series of processes with a flow.

By modifying the contents of the Makefile based on this sample, it is possible to output code corresponding to a processing system other than the Ruby language + Sinatra framework.

First, look for a place that displays {"message": "yes, it worked"} when accessing /search.

Open api/default_api.rb in emacs, etc. and look for the location where the "yes, it worked" message is displayed.

There are two places where it says "yes, it worked", choose the one that corresponds to /search.

Once you have chosen the line to edit, delete the line {"message": "yes, it worked"} and insert the following code. See also the line # the guts live here.

Be careful not to duplicate end.

After saving the modified file, run make PORT=8080 run again.

If the changes were made successfully, you will see the following message as before. If there is a mistake, the Listening on . message will not be displayed, but an error message will be displayed, so compare and correct.

Also open http://localhost:8080/search in a web browser and check the results.

You can also access the API and check the results from a terminal with the following command. This one will be formatted with the jq command, so it should be easier to see.

The output of the curl command has the following nested structure

Once this is done, stop execution of the make run command by typing Ctrl-c, for example.

Now we have a fixed search result for the word sccp. We will make it possible to search for arbitrary keywords later, but first we will change the output.

We will add more processing at the end of the place we just added. The first @result.to_json and the last end are written in api/default_api.rb. Add a line output = erb :main between them.

This time, only one line was added, starting with output.

When you are done, save the file and run the make run command again.

Again access http://localhost:8080/search in your web browser.

You should see a list of search results as follows

Here the display on the screen is controlled by the lib/views/main.erb file.

Currently, only the keyword sccp is searched for and cannot be changed. The following section of the api/default_api.rb file should be changed.

You can change the search results by specifying the keywords you want to search for in the part following q=.

Delete the line above that begins with url = and replace it with the following two lines

Again, start the web server with the make run command, and access the URL, http://localhost:8080/search, by your web browser.

Then, enter an appropriate string in the dialog box at the bottom of the screen and click the "Search" button. The search results will change by using the specified string as a keyword.

As it is now, it is difficult to understand what you are searching for. To improve this, the text field at the bottom of the screen will display the current search string in advance.

Open the file lib/views/main.erb with an editor, such as emacs. Move to the bottom of the file and change the contents of the input tags surrounded by <form …​>〜</form> like as follows.

Save your edits and reload the screen displayed in your web browser to see the results.

ERB is a Ruby-specific function, and this time we are using a highly functional compatible library called Erubi, which adds even more functionality.

By using ERB(Erubi), you can embed Ruby language program codes in various text files. In this case, the code is written directly in the HTML file.

The following code will automatically search for the corresponding file (main.erb) in the lib/views/ directory.

Assigns the contents of the lib/views/main.erb file to the output variable, which executes the embedded program and reflects it in the output.

In general, CSS and JavaScript are used to improve the appearance of Web pages. CSS/JavaScript is not used in the code up to this point.

The reason is that Sinatra does not have the ability to provide external files for CSS and JavaScript. While not technically impossible, it is common practice to prepare a separate web server to serve external files.

Therefore, if you wish to use CSS/JavaScript, the most practical way is to embed the CSS/JavaScript code in the HTML file.

The files used to create the look and feel of the web page within the application are located in the lib/views/ directory. You are free to rewrite any of the files as you wish.

The api/default_api.rb file, equivalent to what you have edited so far, is located at

If you git clone the latest version, it is contained in the docker-sccp-sinatra-sample/ directory.

The following command will catch up with what we have done so far.

The message appears when trying to open the port 8080 that is already in use by opening another terminal and executing make run in duplicate, etc., even though the ``$ make run command has already been executed.

The cause may be that you or another user who has previously used the terminal has left a program running that uses port 8080.

In this case, stop the process that is already using port 8080 so that you can use port 8080.

Pagination is used when the number of items to be displayed exceeds the range of one page.

We need the following information to get the search results to be displayed on the page from an arbitrary starting page number.

If you want to show the current page number, or if you want not to move beyond the last page, you need to use more conditional branches.

For example, you can change the part from @param_q = .. to ret = client.get(url) as follows.

By the following URL, you can get the data from the 11th to the 30th items.

Then, we will add buttons such as "Back to the previous page" and "Next page" to the page.

First, place a file named lib/view/pagination.erb with the following code.

Then, the file lib/views/main.erb calls this file as follows.

You can also add the same code at the bottom of the application.

The Makefile describes the work required to run the application as a Docker container.

The method of using LoadBalancer from a web browser is limited to the total number of EXTERNAL-IPs, so use a reverse proxy prepared by each user.

Please check the following link for details on setting up a reverse proxy.

The proxy_pass line to be added at this time would look like this

Make sure you can access your application via inovtst9.u-aizu.ac.jp as follows

When things go wrong, the steps to be taken are: understand the current situation → analyze → take action.

To do this, you need to have some understanding of what you are trying to do. It may be difficult to get it right, and it may be hard, but please do your best.