Changes for page Your First Rest Project

Summary

• Page properties (2 modified, 0 added, 0 removed)

Details

Page properties

Author

...	...	@@ -1,1 +1,1 @@
1		-XWiki.probert
	1	+XWiki.skcodes

Content

...	...	@@ -1,4 +1,4 @@
1		-{{toc}}{{/toc}}
	1	+{{toc/}}
2	2
3	3	= Introduction =
4	4
...	...	@@ -20,22 +20,93 @@
20	20
21	21	BlogEntry will have the following columns:
22	22
23		-|= Column name |= Type |= Constraints
24		-| id | integer | primary key
25		-| title | string(255) |
26		-| content | string(4000) |
27		-| lastModified | timestamp |
28		-| creationDate | timestamp |
29		-| author | integer | relation with Author
	23	+|=(((
	24	+Column name
	25	+)))|=(((
	26	+Type
	27	+)))|=(((
	28	+Constraints
	29	+)))
	30	+|(((
	31	+id
	32	+)))|(((
	33	+integer
	34	+)))|(((
	35	+primary key
	36	+)))
	37	+|(((
	38	+title
	39	+)))|(((
	40	+string(255)
	41	+)))|(((
	42	+
	43	+)))
	44	+|(((
	45	+content
	46	+)))|(((
	47	+string(4000)
	48	+)))|(((
	49	+
	50	+)))
	51	+|(((
	52	+creationDate
	53	+)))|(((
	54	+timestamp
	55	+)))|(((
	56	+
	57	+)))
	58	+|(((
	59	+lastModified
	60	+)))|(((
	61	+timestamp
	62	+)))|(((
	63	+
	64	+)))
	65	+|(((
	66	+author
	67	+)))|(((
	68	+integer
	69	+)))|(((
	70	+relation with Author
	71	+)))
30	30
31	31	Author will have the following columns:
32	32
33		-|= Column name |= Type |= Constraints
34		-| id | integer | primary key
35		-| firstName | string(50) |
36		-| lastName | string(50) |
37		-| email | string(100) | unique
38		-| passwd | string(16) |
	75	+|=(((
	76	+Column name
	77	+)))|=(((
	78	+Type
	79	+)))|=(((
	80	+Constraints
	81	+)))
	82	+|(((
	83	+id
	84	+)))|(((
	85	+integer
	86	+)))|(((
	87	+primary key
	88	+)))
	89	+|(((
	90	+firstName
	91	+)))|(((
	92	+string(50)
	93	+)))|(((
	94	+
	95	+)))
	96	+|(((
	97	+lastName
	98	+)))|(((
	99	+string(50)
	100	+)))|(((
	101	+
	102	+)))
	103	+|(((
	104	+email
	105	+)))|(((
	106	+string(100)
	107	+)))|(((
	108	+unique
	109	+)))
39	39
40	40	== Creating the EOModel ==
41	41
...	...	@@ -43,7 +43,7 @@
43	43
44	44	An EOModel consists of entities, attributes and relationships. When using it in a RDBMS context, an entity is a table (or a view), an attribute is a table column and a relationship is a join between two tables.
45	45
46		-To create the EOModel, in the project right-click on the project name and select **New** > **EOModel**.
	117	+To create the EOModel, in the project right-click on the project name and select **New** -> **EOModel**.
47	47
48	48	Name it **BlogModel** and in the plugin list, select **H2**. Click **Finish**.
49	49
...	...	@@ -51,8 +51,14 @@
51	51
52	52	If it didn't show up, the window might have opened behind the main Eclipse window. If that's the case, open the **Window** menu and select the windows that have //Entity Modeler// in its name.
53	53
54		-In the Entity Modeler window, click on **Default**, and for the **URL** field, type {{code}}jdbc:h2:~/BlogTutorial{{/code}}. When the database will be created, it will be stored in your home directory (/Users/youruser/ on OS X).
	125	+In the Entity Modeler window, click on **Default**, and for the **URL** field, type
55	55
	127	+{{code}}
	128	+jdbc:h2:~/BlogTutorial
	129	+{{/code}}
	130	+
	131	+. When the database will be created, it will be stored in your home directory (/Users/youruser/ on OS X).
	132	+
56	56	Now, right-click on **BlogModel** and select **New Entity**.
57	57
58	58	Type the following details in the **Basic** tab:
...	...	@@ -73,32 +73,79 @@
73	73
74	74	Now, repeat the last two steps to create the other attributes for the **BlogEntry** entity, with the following values:
75	75
76		-|= Attribute name |= Column |= Prototype
77		-| content | content | longtext
78		-| lastModified | lastModified | dateTime
79		-| creationDate | creationDate | dateTime
	153	+|=(((
	154	+Attribute name
	155	+)))|=(((
	156	+Column
	157	+)))|=(((
	158	+Prototype
	159	+)))
	160	+|(((
	161	+content
	162	+)))|(((
	163	+content
	164	+)))|(((
	165	+longtext
	166	+)))
	167	+|(((
	168	+creationDate
	169	+)))|(((
	170	+creationDate
	171	+)))|(((
	172	+dateTime
	173	+)))
	174	+|(((
	175	+lastModified
	176	+)))|(((
	177	+lastModified
	178	+)))|(((
	179	+dateTime
	180	+)))
80	80
81	81	If you did everything well, the list of attributes should look like this:
82	82
83		-You will notice that the attributes have a column with a lock in it. When a lock is present, it will use the value of that attribute for //UPDATE ... WHERE attribute = ''// statement. This is to do optimistic locking, aka to prevent data conflict when the data object was modified by two different users. Using timestamps for optimistic locking is not a good idea because for certain RDBMS, the value can be different because of milliseconds, so remove the locks on the **lastModified** and **creationDate** attributes. The final list should look like this:
	184	+You will notice that the attributes have a column with a lock in it. When a lock is present, it will use the value of that attribute for //UPDATE ... WHERE attribute = ''// statement. This is to do optimistic locking, aka to prevent data conflict when the data object was modified by two different users. Using timestamps for optimistic locking is not a good idea because for certain RDBMS, the value can be different because of milliseconds, so remove the locks on the **creationDate** attribute. The final list should look like this:
84	84
85	85	Next step is to create the **Author** entity. Create a new entity with **Author** at its name (and also as the table name), and for the class name, use **your.app.model.Author**. The attributes for this entity are:
86	86
87		-|= Attribute name |= Column |= Prototype
88		-| firstName | firstName | varchar50
89		-| lastName | lastName | varchar50
90		-| email | email | varchar100
91		-| passwd | passwd | varchar16
	188	+|=(((
	189	+Attribute name
	190	+)))|=(((
	191	+Column
	192	+)))|=(((
	193	+Prototype
	194	+)))
	195	+|(((
	196	+firstName
	197	+)))|(((
	198	+firstName
	199	+)))|(((
	200	+varchar50
	201	+)))
	202	+|(((
	203	+lastName
	204	+)))|(((
	205	+lastName
	206	+)))|(((
	207	+varchar50
	208	+)))
	209	+|(((
	210	+email
	211	+)))|(((
	212	+email
	213	+)))|(((
	214	+varchar100
	215	+)))
92	92
93	93	Final list of attributes should look like this:
94	94
95		-Now, it's time to link the two entities together. A Author can have multiple blog entries, and a BlogEntry can only have one author. To create the relationship (the join), right-click on **Author** and select **New Relationship**. On your right, select **BlogEntry** in the list. On your left, select **to many BlogEntries**, and on your left, select **to one Author**. Now, in BlogEntry, we need to store the primary key of the author so that we can make the join. The relationship builder allow us to add that attribute, so make sure **and a new foreign key named** is checked (it is checked by default). The **Create Relationship** pane should look like this:
	219	+Now, it's time to link the two entities together. An Author can have multiple blog entries, and a BlogEntry can only have one author. To create the relationship (the join), right-click on **Author** and select **New Relationship**. On your right, select **BlogEntry** in the list. On your left, select **to many BlogEntries**, and on your right, select **to one Author**. Now, in BlogEntry, we need to store the primary key of the author so that we can make the join. The relationship builder allow us to add that attribute, so make sure **and a new foreign key named** is checked (it is checked by default). The **Create Relationship** pane should look like this:
96	96
97	97	If you check in the **Outline** tab, you should see that **Author** now have a **blogEntries** relationship, and **BlogEntry** have a **author** relationship.
98	98
99		-You are now ready to save the model. Save it (File > Save) and close the **Entity Modeler** window. If you open the **Sources** in the main Eclipse window, you will notice that the **Sources** folder contains a package named **your.app.model**.
	223	+You are now ready to save the model. Save it (File -> Save) and close the **Entity Modeler** window. If you open the **Sources** in the main Eclipse window, you will notice that the **Sources** folder contains a package named **your.app.model**. (If this folder doesn't appear, you may need to set your preferences to automatically generate these source files; see the second suggestion on [[http:~~/~~/wiki.wocommunity.org/display/documentation/Useful+Eclipse+or+WOLips+Preferences>>url:http://wiki.wocommunity.org/display/documentation/Useful+Eclipse+or+WOLips+Preferences||rel="nofollow" shape="rect" class="external-link"]].)
100	100
101		-That package have four Java classes: **Author**, **Author**, **BlogEntry** and **BlogEntry**. Those classes were generated by Veogen, a templating engine build on Velocity. The two classes that starts with a underscore are recreated every time you change the EOModel, so if you want to change something in those classes, you need to change the template (no need for that right now). But you can change freely the two classes that don't have the underscore, and this is what we will be doing.
	225	+That package have four Java classes: **_Author**, **Author**, **_BlogEntry** and **BlogEntry**. Those classes were generated by Veogen, a templating engine build on Velocity. The two classes that starts with a underscore are recreated every time you change the EOModel, so if you want to change something in those classes, you need to change the template (no need for that right now). But you can change freely the two classes that don't have the underscore, and this is what we will be doing.
102	102
103	103	What we are going to do is to write a simple method that returns the full name of an author, e.g. a method that simply concatenate the first name, a space and the last name of the author. To do so, double-click on **Author.java** and add the following methods:
104	104
...	...	@@ -110,11 +110,27 @@
110	110
111	111	{{/code}}
112	112
113		-Nothing fancy here. Now, let's use migrations to actually create the database.
	237	+Nothing fancy here. Now open **BlogEntry.java** and add the following method:
114	114
	239	+{{code}}
	240	+
	241	+ @Override
	242	+ public void awakeFromInsertion(EOEditingContext editingContext) {
	243	+ super.awakeFromInsertion(editingContext);
	244	+ NSTimestamp now = new NSTimestamp();
	245	+ setCreationDate(now);
	246	+ setLastModified(now);
	247	+ }
	248	+
	249	+{{/code}}
	250	+
	251	+Why are we adding this? **awakeFromInsertion** is a very good way of setting default values when creating a new instance of a Enterprise Object (EO). In this case, we want to set automatically the creation and last modification dates without having the user to add those values.
	252	+
	253	+Now, let's use migrations to actually create the database.
	254	+
115	115	== Using migrations ==
116	116
117		-Migrations allow you to create the tables and columns (and some types of constraint). **Entity Modeler** have support to generate the code for the first migration, which is called "migration 0". To do that, open the EOModel (**BlogModel EOModel** in the **Resources** folder), right-click on the model name and select **Generate Migration**.
	257	+Migrations allow you to create the tables and columns (and some types of constraint). **Entity Modeler** has support to generate the code for the first migration, which is called "migration 0". To do that, open the EOModel (**BlogModel EOModel** in the **Resources** folder), right-click on the model name and select **Generate Migration**.
118	118
119	119	Copy the generated code in the clipboard. Close **Entity Modeler** and in the main Eclipse window, right-click on **Sources**, select **New** and select **Class**.
120	120
...	...	@@ -142,14 +142,14 @@
142	142
143	143	{{/code}}
144	144
145		-You are now ready to start the application so that it creates the database To do so, right-click on **Application.java** (in the **your.app** folder) and select **Run As** > **WOApplication**. In Eclipse's Console tab, you should see some output, including something similar to:
	285	+You are now ready to start the application so that it creates the database! To do so, right-click on **Application.java** (in the **your.app** folder) and select **Run As** -> **WOApplication**. In Eclipse's Console tab, you should see some output, including something similar to:
146	146
147	147	{{code}}
148	148
149	149	BlogRest[62990] INFO er.extensions.migration.ERXMigrator - Upgrading BlogModel to version 0 with migration 'your.app.model.migrations.BlogModel0@4743bf3d'
150		-BlogRest[62990] INFO er.extensions.jdbc.ERXJDBCUtilities - Executing CREATE TABLE Author(email VARCHAR(100) NOT NULL, firstName VARCHAR(50) NOT NULL, id INTEGER NOT NULL, lastName VARCHAR(50) NOT NULL, passwd VARCHAR(16) NOT NULL)
	290	+BlogRest[62990] INFO er.extensions.jdbc.ERXJDBCUtilities - Executing CREATE TABLE Author(email VARCHAR(100) NOT NULL, firstName VARCHAR(50) NOT NULL, id INTEGER NOT NULL, lastName VARCHAR(50) NOT NULL)
151	151	BlogRest[62990] INFO er.extensions.jdbc.ERXJDBCUtilities - Executing ALTER TABLE Author ADD PRIMARY KEY (id)
152		-BlogRest[62990] INFO er.extensions.jdbc.ERXJDBCUtilities - Executing CREATE TABLE BlogEntry(authorID INTEGER NOT NULL, content TIMESTAMP NOT NULL, creationDate TIMESTAMP NOT NULL, id INTEGER NOT NULL, lastModified TIMESTAMP NOT NULL, title VARCHAR(255) NOT NULL)
	292	+BlogRest[62990] INFO er.extensions.jdbc.ERXJDBCUtilities - Executing CREATE TABLE BlogEntry(authorID INTEGER NOT NULL, content TIMESTAMP NOT NULL, creationDate TIMESTAMP NOT NULL, id INTEGER NOT NULL, title VARCHAR(255) NOT NULL)
153	153	BlogRest[62990] INFO er.extensions.jdbc.ERXJDBCUtilities - Executing ALTER TABLE BlogEntry ADD PRIMARY KEY (id)
154	154	BlogRest[62990] INFO er.extensions.jdbc.ERXJDBCUtilities - Executing ALTER TABLE BlogEntry ADD CONSTRAINT "FOREIGN_KEY_BLOGENTRY_AUTHORID_AUTHOR_ID" FOREIGN KEY (authorID) REFERENCES Author (id)
155	155	BlogRest[62990] DEBUG NSLog - evaluateExpression: <er.h2.jdbcadaptor.ERH2PlugIn$H2Expression: "UPDATE _dbupdater SET version = ? WHERE modelname = ?" withBindings: 1:0(version), 2:"BlogModel"(modelName)>
...	...	@@ -156,7 +156,7 @@
156	156
157	157	{{/code}}
158	158
159		-If you see this and that the application is running (it should open a window in your favorite browser), migration worked and your database have been created, congratulations You can now stop the application (click the square red button in Eclipse's Console tab) and continue to the next step.
	299	+If you see this and that the application is running (it should open a window in your favorite browser), migration worked and your database have been created, congratulations! You can now stop the application (click the square red button in Eclipse's Console tab) and continue to the next step.
160	160
161	161	= Creating REST controllers and routes =
162	162
...	...	@@ -178,14 +178,247 @@
178	178	You can shorten the URL by using mod_rewrite in Apache httpd
179	179	{{/info}}
180	180
181		-.
182		-
183	183	== Creating controllers ==
184	184
185	185	ERRest needs controllers to act as a broker between working with the objects and the routes. So let's create a controller for BlogEntry.
186	186
	325	+Create a Java class named **BlogEntryController**, in the **your.app.rest.controllers** package, that will extend from **er.rest.routes.ERXDefaultRouteController**. Click **Finish**.
	326	+
	327	+When you extend from **ERXDefaultRouteController**, a bunch of methods are added to the subclass. Let's see what they are for.
	328	+
	329	+* **updateAction**: to update a specific instance of BlogEntry
	330	+* **destroyAction**: to delete a specific instance of BlogEntry
	331	+* **showAction**: to get one specific instance of BlogEntry
	332	+* **createAction**: to create a new object (a new instance of BlogEntry)
	333	+* **indexAction**: to list all (or a sublist) of the objects.
	334	+
	335	+{{info}}
	336	+In Project Wonder, **Action** at the end of a method is a convention for REST and Direct Actions, when you call those methods from certain components, you don't need to add the **Action** part.
	337	+{{/info}}
	338	+
	339	+For this tutorial, we will implement the **createAction** and **indexAction** methods. But first, we need to create a key filter. A key filter will... filter the input and the output of REST request so that you don't have to send all attributes for a blog entry. For example, we want to show the details for an author, but we don't want to show the password for the author (in real-life, the password would be encrypted)!
	340	+
	341	+Add this method in **BlogEntryController**:
	342	+
	343	+{{code}}
	344	+
	345	+protected ERXKeyFilter filter() {
	346	+ ERXKeyFilter personFilter = ERXKeyFilter.filterWithAttributes();
	347	+ personFilter.setAnonymousUpdateEnabled(true);
	348	+
	349	+ ERXKeyFilter filter = ERXKeyFilter.filterWithAttributes();
	350	+ filter.include(BlogEntry.AUTHOR, personFilter);
	351	+ filter.setUnknownKeyIgnored(true);
	352	+
	353	+ return filter;
	354	+ }
	355	+
	356	+{{/code}}
	357	+
	358	+Now, let's implement the **createAction** method:
	359	+
	360	+{{code}}
	361	+
	362	+public WOActionResults createAction() throws Throwable {
	363	+ BlogEntry entry = create(filter());
	364	+ editingContext().saveChanges();
	365	+ return response(entry, filter());
	366	+ }
	367	+
	368	+{{/code}}
	369	+
	370	+In 3 lines of code, you can create an object based on the request, save the new object to the database and return the new object in the response. Not bad, eh?
	371	+
	372	+Last step in the controller: implementing the **indexAction** method. Again, the code is simple:
	373	+
	374	+{{code}}
	375	+
	376	+public WOActionResults indexAction() throws Throwable {
	377	+ NSArray<BlogEntry> entries = BlogEntry.fetchAllBlogEntries(editingContext());
	378	+ return response(entries, filter());
	379	+ }
	380	+
	381	+{{/code}}
	382	+
	383	+That code simply fetch all blog entries and return them in the response.
	384	+
	385	+We can now go to the next step: adding the routes.
	386	+
187	187	== Adding the routes ==
188	188
	389	+A route in ERRest is simply a way to define the URL for the entities and to specify which controller the route should use. When your controller extends from **ERXDefaultRouteController**, it's easy to register a controller and a route. In **Application.java**, in the **Application** constructor, add the following code:
	390	+
	391	+{{code}}
	392	+
	393	+ERXRouteRequestHandler restRequestHandler = new ERXRouteRequestHandler();
	394	+ restRequestHandler.addDefaultRoutes(BlogEntry.ENTITY_NAME);
	395	+ ERXRouteRequestHandler.register(restRequestHandler);
	396	+ setDefaultRequestHandler(restRequestHandler);
	397	+
	398	+{{/code}}
	399	+
	400	+The **addDefaultRoutes** method do all of the required magic, and use convention. That's why we had to name the controller **BlogEntryController**, because the convention is <EntityName>Controller.
	401	+
	402	+We are now reading to add and list blog postings! Start the application and take notice of the URL. It should be something like _[[http:~~/~~/yourip:someport/cgi-bin/WebObjects/BlogRest.woa_>>url:http://yourip:someport/cgi-bin/WebObjects/BlogRest.woa_||shape="rect"]]
	403	+
189	189	== Adding posts and authors with curl ==
190	190
	406	+Since we didn't implement any HTML for our REST routes, we will create blog entries with //curl//, an open source HTTP client that is bundled with Mac OS X (you can use another client, like wget, if you like too). So let's create a blog entry.
	407	+
	408	+To create a blog entry, you need to use the POST HTTP method. We will use JSON as the format since it's a bit less chatty than XML. So if the URL to the application is //[[http:~~/~~/192.168.0.102:52406/cgi-bin/WebObjects/BlogRest.woa_>>url:http://192.168.0.102:52406/cgi-bin/WebObjects/BlogRest.woa_||shape="rect"]], the full _curl// command will be:
	409	+
	410	+{{code}}
	411	+curl -X POST -v -d '{ "title": "First post", "content": "Some text", "author": { "firstName": "Pascal", "lastName": "Robert", "email": "probert@macti.ca" } }' http://192.168.0.102:52406/cgi-bin/WebObjects/BlogRest.woa/ra/blogEntries.json
	412	+{{/code}}
	413	+
	414	+The response should look this:
	415	+
	416	+{{code}}
	417	+
	418	+HTTP/1.0 201 Apple WebObjects
	419	+Content-Length: 249
	420	+x-webobjects-loadaverage: 0
	421	+Content-Type: application/json
	422	+
	423	+{"id":1,"type":"BlogEntry","content":"Some text","creationDate":"2011-12-27T21:59:08Z","title":"First post","author":{"id":1,"type":"Author","email":"probert@macti.ca","firstName":"Pascal","lastName":"Robert"}}
	424	+
	425	+{{/code}}
	426	+
	427	+To get a list of blog entries:
	428	+
	429	+{{code}}
	430	+
	431	+curl -X GET http://192.168.0.102:52406/cgi-bin/WebObjects/BlogRest.woa/ra/blogEntries.json
	432	+
	433	+{{/code}}
	434	+
	435	+You can stop the application and proceed to the next step.
	436	+
191	191	== Adding HTML views for blog posts ==
	438	+
	439	+Now, let's build a HTML view for blog posts (you don't want your readers to get your posts by JSON, right?). Again, we will use convention to make it work easily. Open up **BlogEntryController** and add the following method:
	440	+
	441	+{{code}}
	442	+
	443	+@Override
	444	+ protected boolean isAutomaticHtmlRoutingEnabled() {
	445	+ return true;
	446	+ }
	447	+
	448	+{{/code}}
	449	+
	450	+Switching the return value of this method says that we will follow a certain convention for HTML components. The convention for automatic HTML routing is that the component should be named <EntityName><Action>Page.wo. So in our case, the component will be **BlogEntryIndexPage**. Right-click on the project name in Eclipse and select **New** -> **WOComponent**. Change the name to **BlogEntryIndexPage** and check the **Create HTML contents** button. Click **Finish**.
	451	+
	452	+The next step to get it to work is to make **BlogEntryIndexPage** to implement the **er.rest.routes.IERXRouteComponent** interface.
	453	+
	454	+{{code}}
	455	+
	456	+import er.rest.routes.IERXRouteComponent;
	457	+
	458	+public class BlogEntryIndexPage extends WOComponent implements IERXRouteComponent {
	459	+
	460	+{{/code}}
	461	+
	462	+So now, the automatic HTML routing will send the request for **ra/blogEntries.html** to the **BlogEntryIndexPage** component. But we don't have any content in this component, so let's make a method to fetch all blog entries per creation date in descending order. So in **BlogEntryIndexPage.java**, add the following method:
	463	+
	464	+{{code}}
	465	+
	466	+public NSArray<BlogEntry> entries() {
	467	+ EOEditingContext ec = ERXEC.newEditingContext();
	468	+ return BlogEntry.fetchAllBlogEntries(ec, BlogEntry.CREATION_DATE.descs());
	469	+ }
	470	+
	471	+{{/code}}
	472	+
	473	+We need to use that method in a WORepetition, and for that loop, we need a BlogEntry variable to iterate in the list, so add the following code to **BlogEntryIndexPage.java**:
	474	+
	475	+{{code}}
	476	+
	477	+private BlogEntry entryItem;
	478	+
	479	+ public BlogEntry entryItem() {
	480	+ return entryItem;
	481	+ }
	482	+
	483	+ public void setEntryItem(BlogEntry entryItem) {
	484	+ this.entryItem = entryItem;
	485	+ }
	486	+
	487	+{{/code}}
	488	+
	489	+The Java part is done, so let's add the loop inside the component. Open **BlogEntryIndexPage.wo** (it's located in the **Component** folder) and right after the <body> tag, add:
	490	+
	491	+{{code}}
	492	+
	493	+<wo:loop list="$entries" item="$entryItem">
	494	+ <p><wo:str value="$entryItem.title" /></p>
	495	+ <p><wo:str value="$entryItem.author.fullName" /></p>
	496	+ </wo:loop>
	497	+
	498	+{{/code}}
	499	+
	500	+That component code will loop over the blog entries and display the title of the entry + the name of the author. Save everything and run the application.
	501	+
	502	+If you go to [[http:~~/~~/192.168.0.102:52406/cgi-bin/WebObjects/BlogRest.woa/ra/blogEntries.html>>url:http://192.168.0.102:52406/cgi-bin/WebObjects/BlogRest.woa/ra/blogEntries.html||shape="rect"]], you will see the list of blog entries!
	503	+
	504	+Now that we have a list of blog entries, let's make a page to show the content of a blog entry. Create a new component named **BlogEntryShowPage**.
	505	+
	506	+Open **BlogEntryShowPage.java** and make sure the class implements **er.rest.routes.IERXRouteComponent**.
	507	+
	508	+{{code}}
	509	+
	510	+import er.rest.routes.IERXRouteComponent;
	511	+
	512	+public class BlogEntryShowPage extends WOComponent implements IERXRouteComponent {
	513	+
	514	+{{/code}}
	515	+
	516	+We need to add other methods to receive the BlogEntry object from the controller. In **BlogEntryShowPage.java**, add:
	517	+
	518	+{{code}}
	519	+
	520	+private BlogEntry blogEntry;
	521	+
	522	+ @ERXRouteParameter
	523	+ public void setBlogEntry(BlogEntry blogEntryFromController) {
	524	+ this.blogEntry = blogEntryFromController;
	525	+ }
	526	+
	527	+ public BlogEntry blogEntry() {
	528	+ return this.blogEntry;
	529	+ }
	530	+
	531	+{{/code}}
	532	+
	533	+The **@ERXRouteParameter** annotation tells the REST framework that it can automatically receive an object from the controller. And again, it's convention at work. You have to use the annotation and the setter name should be //set<EntityName>//, so for a BlogEntry, it's //setBlogEntry//, for a Author, it will be //setAuthor//.
	534	+
	535	+The Java part of the work is done, so save the Java class. It's time to work on the component part. Open **BlogEntryShowPage.wo** and between the <body></body> part, add:
	536	+
	537	+{{code}}
	538	+
	539	+<h1><wo:str value="$blogEntry.title" /></h1>
	540	+ <p><wo:str value="$blogEntry.content" /></p>
	541	+ <p>Created on: <wo:str value="$blogEntry.creationDate" dateformat="%Y/%m/%d" /></p>
	542	+ <p>Added by: <wo:str value="$blogEntry.author.fullName" /></p>
	543	+
	544	+{{/code}}
	545	+
	546	+Our view component is done, the only thing remaining is a link for the blog entry list (BlogEntryIndexPage) to the view page (BlogEntryShowPage). Save **BlogEntryShowPage.wo** and open **BlogEntryIndexPage.wo**. We are going to add a link on the title, you will replace to replace this:
	547	+
	548	+{{code}}
	549	+
	550	+<p><wo:str value="$entryItem.title" /></p>
	551	+
	552	+{{/code}}
	553	+
	554	+with:
	555	+
	556	+{{code}}
	557	+
	558	+<p><wo:ERXRouteLink entityName="BlogEntry" record="$entryItem" action="show"><wo:str value="$entryItem.title" /></wo:ERXRouteLink></p>
	559	+
	560	+{{/code}}
	561	+
	562	+Save the component and run the app. Go to [[http:~~/~~/192.168.0.102:52406/cgi-bin/WebObjects/BlogRest.woa/ra/blogEntries.html>>url:http://192.168.0.102:52406/cgi-bin/WebObjects/BlogRest.woa/ra/blogEntries.html||shape="rect"]] to get the list of posts, and you should see a link on the title. Click on it, and now you get the full details of the blog entry!
	563	+
	564	+The REST part of this tutorial is now complete, [[you can now move to the next part of the tutorial>>doc:Your First Framework]].